이 작품은 (DEC에) R35GM119617을 부여 토마스 F.와 케이트 밀러 제프리스 Memoria (DEC에) 신뢰와 NIH에 의해 지원되었다. 공 초점 현미경 영상은 VCU 나노 물질 특성 코어 (NCC) 시설에서 수행되었다.

1. Nesprin-2G 센서 DNA 및 다른 플라스미드 DNA를 구합니다 <ol><li> 상업적인 소스로부터 Nesprin 2G-TS (인장 센서) Nesprin HL-2G (헤드리스) 제어 mTFP1 금성 및 TSmod를 구합니다. 모든 DNA 플라스미드를 전파 이전 12,13 바와 같이, 이러한 DH5-α 표준 E. 콜라이 균주를 사용하여 정제. </li></ol> Nesprin-2G 및 기타 플라스미드 DNA 2. 형질 세포 <ol><li> 온도 (37 ° C) 및 CO 2 5 %로 규제 표준 세포 배양 인큐베이터에서 6- 웰 세포 배양 접시에 70-90 %의 합류점에 NIH 3T3 섬유 아세포의 세포 성장. 세포 성장 매체의 경우, 10 % 소 태아 혈청 둘 베코의 변형 이글 중간 (DMEM)을 사용합니다. </li><li> 세포 배양 후드에서, 배지를 제거하고 감소 된 혈청 배지 세포의 약 1 mL로 각 웰을 씻어. 각 웰에 감소 혈청 세포 매체의 800 μL를 추가상기 인큐베이터에서 6- 웰 챔버를 배치했다. </li><li> 지질 담체 용액 35 μL와 함께 1.5 ㎖의 튜브에 감소 된 혈청 세포 배지 700 μL 피펫은 &quot;lipomix&quot;를 형성한다. 피펫으로 섞는다. 에 &quot;L.&quot;로 튜브 라벨 </li><li> 여섯 개 1.5 ㎖의 튜브를 수집하고, 각 관으로 감소 된 혈청 세포 배지 6 μL 피펫 (100)을 통해 1 라벨. <ol><li> mVenus 항 피펫 1 μg의 튜브에 튜브 (3) 및 제 피펫 1 mTFP의 μg의로 튜브 1 및 2 피펫 2 Nesprin-HL의 μg의 한 단계 1 피펫 2 Nesprin 2G-TS의 μg의으로부터 플라스미드 DNA의 농도를 사용하여 튜브 (6)에 다시 사용하지 마십시오 피펫 팁을 DNA의 다른 유형을 피펫 팅 할 때. </li></ol></li><li> 각 분류 관 (1-6)에 &quot;L&quot;튜브로부터 lipomix 100 μL 피펫 및 피펫 팅을 반복하여 혼합한다. 각 튜브에 대한 깨끗한 피펫을 사용합니다. 10 ~ 20 분 동안 품어. </li><li> 70-90 % 합류로 6 웰 챔버의 웰에 각각 분류 관에서 200 μL를 추가세포. 해당 DNA와 각 웰의 상부에 라벨했다. 4-6 시간 동안 인큐베이터에서 6- 웰 챔버를 놓는다. </li><li> 배지를 흡인하고 린스 감소 된 혈청 배지 셀 1-2 mL를 첨가. 상기 감소 된 - 혈청 배지를 세포 기음 각 웰에 트립신 2 mL를 첨가하고, 인큐베이터 (5-15 분)로 6 웰 접시를 배치했다. </li><li> 세포 배양기에서 분리되지만, 피막 (6) 유리 바닥은 인산 완충 용액 (PBS)에 용해 된 20 ㎍ / ml의 농도에서 피브로넥틴의 층으로 요리를보고. 코팅하는 요리를 세포 배양 후드 (약 20 분)의 표면을 허용한다. </li><li> 세포가 분리되면 DMEM 2 용액을 첨가함으로써 트립신을 중성화. </li><li> 또한 표지 된 15 mL의 원심 분리 튜브에 각각의 콘텐츠를 전송하고 스윙 로터 원심 분리기에서 5 분 동안 90 XG에서 스핀 다운. 상등액을 흡인 피펫 혼합하여 DMEM 1000 μL의 각 세포 펠렛을 다시 일시. </li><li> 로부터 피브로넥틴 혼합물 기음유리 접시 피펫 유리 접시 상에 각 세포 현탁액을 1000 μL. </li><li> 세포가 유리 접시의 바닥 (~ 15 분)에 정착 한 후, 세포 배양기에서 잘 장소 각각 다른 DMEM 1 ㎖의 + 10 % FBS + 1 % 스트렙토 펜을 추가한다. 세포가 적어도 18 ~ 24 시간 동안 센서를 부착하고 표현 할 수 있습니다. 참고 : 세포 상업 양이온 성 지질 형질 전환 시약 (재료의 표 참조)을 사용하여 형질 전환된다. 대안 적으로, 안정한 세포주는 독소에 대한 내성을 부여하는 유전자를 가진 플라스미드를 사용하여 선택 될 수있다 (Nesprin-TS와 -hl 대한 pcDNA 벡터 플라스미드 네티 신 내성을 발현하는 세포 (물질의 표를 참조)를 제공하는 DNA 저장소 사이트에서 사용할 ). 또한 바이러스 감염 방법 (렌티 바이러스, 레트로 바이러스 또는 아데노 바이러스)를 형질 어렵다 셀 센서를 표현하는데 이용 될 수있다. </li><li> Nesprin-TS 외에도 Nesprin HL 제로위한 부가적인 세포를 형질CE 제어 2.1-2.12 단계에서 설명한 바와 같이, TSmod 또한 제로 - 힘 제어로 사용될 수 Nesprin HL-유사한 FRET을 발휘한다. </li><li> mTFP1 금성로 형질 세포 스펙트럼 지문 (단계 4 참조)를 생성한다. 참고 mTFP1 금성은 일반적 Nesprin-TS보다 높은 수준의 발현과 같은 DNA의 하부 양 유사한 발현 수준을 달성하기 위해 형질 전환 될 필요가있다. </li></ol> 3. 형질 전환 효율을 확인 <ol><li> 대략 18-24 시간 형질을 마친 후,도 셀 (통상 5-30 %)의 총 수에 형광 세포의 수를 비교하여 형질 전환의 효율을 조사하기 반전 형광 현미경을 사용한다. <ol><li> 462 나노 미터 (mTFP1) 또는 525 나노 미터 (금성) 및 492 nm의 (mTFP1) 또는 525 나노 미터 (금성) 근처에 중심 발광 필터 근처의 여기 주파수가 장착 된 형광 현미경을 사용한다. 참고 : 또는 GFP 필터 세트 mTFP1의 조합을 캡처했습니다 것NUS 배출량은 형질 전환 효율의 확인을 허용합니다. </li></ol></li><li> 형질 전환 후 48 시간 내에 이미지 살아있는 세포. <ol><li> 대안 적으로, 48 시간 후 8 PBS에서 5 분간, 상점, 볼 (칼슘 및 마그네슘과 PBS)에서 4 % 파라 포름 알데히드로 세포를 고정한다. 참고 : 48 시간을 넘어, 신호 품질 및 강도는 붕괴. 세포를 고정하기 (8)로 표현되는 FRET 포함한 상태를 유지; 매체를 장착하여 FRET (14)에 영향을 미칠 수있다 그러나, 셀은, PBS에 이미징되어야한다. 표정의 변화가있을 수에 따라 고정 셀은 다른 셀에 고정 비교 될 수있다. 주의 : 파라 포름 알데히드는 독성이있다. 적절한 개인 보호 장비 (PPE)를 착용 할 것. </li></ol></li></ol> 스펙트럼 Unmixing에 대한 mTFP1과 금성 형광 발색단 4. 캡처 스펙트럼 지문 <ol><li> 세포 배양 후드에서 촬상 mediu와 세포 배지를 교체10 % 소 태아 혈청 m (HEPES 완충). </li><li> 온도 제어 (37 ° C) 공 초점 레이저 주사 현미경 단계에서 보는 요리를 놓는다. </li><li> 1.4 개구 수 60X 배율 오일 대물 위에 mTFP1 형질 세포 유리 뷰잉 접시 놓는다. 주 : 오일 밀접 유리 기판의 굴절률이 유사 할 60X 대물 렌즈에 레이저 스캐닝 현미경에 사용된다. 오일은 대물 렌즈의 상단에 배치하고 유리 커버 슬립과 직접 접촉한다. </li><li> mTFP1는 458 nm의 여기 원 및 500 nm의 발광 중심 대역 통과 필터로 발현 세포를 찾아. </li><li> 시야에서 형광 셀 (여기에서 사용되는 소프트웨어 &quot;람다 모드&quot;) 스펙트럼 검출 모드를 선택하고, 분광 화상 (도 3-1)을 캡처; 10 개 나노 미터 단위 (도 3-3)을 이용하여 458 nm의 이후의 모든 주파수를 포함한다. 밝은 fluoresc를 선택셀 (20 화소 반경)에 ENT 영역 (ROI). 참고 : mTFP1 발현 투자 수익 (ROI)의 스펙트럼 형태는 셀에 걸쳐 상대적으로 일정하게 유지해야한다. 형상이 현저하게 변화되면, 레이저를 재조정하고, 신호 대 잡음비를 개선하기 위해 설정을 얻는다. </li><li> 클릭하여 스펙트럼 데이터베이스에, 형광 ROI 의미 정규화 강도를 추가 &quot;데이터베이스에 스펙트럼을 저장합니다.&quot; </li><li> 레이저 파워를 최적화하고 양호한 신호 대 잡음비가 성취되도록 얻는다. 설정은 다른 장비에 따라 다를 것입니다. 배경 기준으로 비 - 형광, 형질 감염되지 않은 세포를 사용하여, 그러나, 검출기 (포화)의 동적 범위를 넘어, 세포가 밝은 때까지 상기 이득과 전력을 증가시킨다. 배경 세포는 평균 후 감지 형광 없어야합니다. </li><li> 다음을 제외 금성 - 형질 전환 된 세포의 과정을 반복합니다 : <ol><li> 여기 주파수가 515 nm에서인지 확인하고, 밴드 패스 필터는 CE라고금성 발현 세포를 찾을 때 530 나노 미터 근처 ntered. </li><li> 의 &quot;스펙트럼 모드&quot;내지 515 대신 458 nm 인 여기 주파수를 사용한다. </li></ol></li></ol> 5. 캡처 혼합하지 않은 이미지 <ol><li> 에 캡처 모드 전환 &quot;스펙트럼 Unmixing을.&quot; </li><li> unmixing 채널로 (도 3, 화살표 2) 금성 mTFP1의 스펙트럼 지문을 추가한다. </li><li> 다시 458 nm의 아르곤 소스 여진 레이저를 설정한다. </li><li> 60X 오일 대물 위 Nesprin-TS 볼 접시 놓는다. </li><li> 충분히 밝은 식 형광 세포에 집중하면, 신호 대 잡음비를 최적화하는 게인 및 레이저 파워를 조정한다. 참고 Nesprin-TS의 FRET 효율은 20 % 가까이 있기 때문에, 혼합되지 않은 금성 화상이 섞이지 mTFP1 이미지보다 실질적으로 더 어둡게 될 것이다. 허용 전력 및 이득 설정이 반복적으로 결정되면, 이들 매개 변수는 모두 이미지 대위에 대한 일정하게 유지해야ured. </li><li> (모든 포화 화소 화상 처리 동안 제거되는) 비교적 유사한 밝기 Nesprin-TS 셀 15-20 이미지 캡처 최소 화소 과도한 포화를 방지. </li><li> 동일한 촬상 파라미터를 사용하여 HL-Nesprin 세포 촬상 처리를 반복한다. </li></ol> 6. 이미지 프로세싱 및 비율 이미지 분석 <ol><li> 사용하여 오픈 소스 ImageJ에 (피지) 소프트웨어 (http://fiji.sc/), BioFormats Reader를 사용하여 열려있는 기본 형식 이미지. </li><li> 전 과정을 이미지와는 이전에 설정된 프로토콜 15을 사용하는 비율 이미지를 계산한다. </li></ol>

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D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purifying+plasmid+DNA+from+bacterial+colonies+using+the+QIAGEN+Miniprep+Kit.">Purifying plasmid DNA from bacterial colonies using the QIAGEN Miniprep Kit.</a> J Vis Exp. (6), e247 (2007).</li><li>Rodighiero, S., Bazzini, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fixation,+mounting+and+sealing+with+nail+polish+of+cell+specimens+lead+to+incorrect+FRET+measurements+using+acceptor+photobleaching.">Fixation, mounting and sealing with nail polish of cell specimens lead to incorrect FRET measurements using acceptor photobleaching.</a> Cell. Physiol. Biochem. 21 (5-6), 489-498 (2008).</li><li>Kardash, E., Bandemer, J., Raz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+protein+activity+in+live+embryos+using+fluorescence+resonance+energy+transfer+biosensors.">Imaging protein activity in live embryos using fluorescence resonance energy transfer biosensors.</a> Nat Protoc. 6 (12), 1835-1846 (2011).</li><li>Vaziri, A., Mofrad, M. R. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanics+and+deformation+of+the+nucleus+in+micropipette+aspiration+experiment.">Mechanics and deformation of the nucleus in micropipette aspiration experiment.</a> J Biomech. 40 (9), 2053-2062 (2007).</li><li>Wang, N., Naruse, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+behavior+in+living+cells+consistent+with+the+tensegrity+model.">Mechanical behavior in living cells consistent with the tensegrity model.</a> Proc. Natl. Acad. Sci. U.S.A. 98 (14), 7765-7770 (2001).</li><li>Nagayama, K., Yahiro, Y., Matsumoto, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress+fibers+stabilize+the+position+of+intranuclear+DNA+through+mechanical+connection+with+the+nucleus+in+vascular+smooth+muscle+cells.">Stress fibers stabilize the position of intranuclear DNA through mechanical connection with the nucleus in vascular smooth muscle cells.</a> FEBS letters. 585 (24), 3992-3997 (2011).</li><li>Luxton, G. W. G., Gomes, E. R., Folker, E. S., Vintinner, E., Gundersen, G. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Linear+arrays+of+nuclear+envelope+proteins+harness+retrograde+actin+flow+for+nuclear+movement.">Linear arrays of nuclear envelope proteins harness retrograde actin flow for nuclear movement.</a> Science. 329 (5994), 956-959 (2010).</li><li>Chen, Y., Mauldin, J. P., Day, R. N., Periasamy, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+spectral+FRET+imaging+microscopy+for+monitoring+nuclear+protein+interactions.">Characterization of spectral FRET imaging microscopy for monitoring nuclear protein interactions.</a> J Microsc. 228, 139-152 (2007).</li><li>Ran, F. A., Hsu, P. D., Wright, J., Agarwala, V., Scott, D. A., Zhang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genome+engineering+using+the+CRISPR-Cas9+system.">Genome engineering using the CRISPR-Cas9 system.</a> Nat Protoc. 8 (11), 2281-2308 (2013).</li><li>LaCroix, A. S., Rothenberg, K. E., Berginski, M. E., Urs, A. N., Hoffman, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction,+imaging,+and+analysis+of+FRET-based+tension+sensors+in+living+cells.">Construction, imaging, and analysis of FRET-based tension sensors in living cells.</a> Methods Cell Biol. , (2015).</li></ol>

The authors have nothing to disclose.

방법 및 Nesprin-2G 핵 LINC 복잡 단백질 걸쳐 기계적 장력 생균 촬상 시연은 위에서 언급되었다. 이전이 연구에, 이러한 마이크로 피펫 흡인 세포 계측법, 자성 비드, 현미경 레이저 절제와 같은 다양한 기술들은, 세포핵에 변형을 적용하고, 벌크 물성 16, 17, 18을 측정하기 위해 사용되었다. 그러나, 최근의 작품까지, 어떤...

포스 성 유전자 부호화 FRET 센서 최근 생균 인장 계의 힘을 측정하는 단백질 1, 2, 3, 4에인가되는 방법을 기계적 힘에 대한 통찰력을 제공하기위한 중요한 도구로 떠오르고있다. 이러한 도구를 사용하여, 연구자들은 기존의 형광 현미경을 이용하여 살아있는 세포에서 비 침습적 영상 세포 내 힘 수 있습니다. 이러한 센서는 탄성 펩티드 (3)에 의해 분리 된 FRET 쌍 (도너와 억 셉터 형광 단백질, 자주 청색 공여체 및 수용체 노란색)로 구성된다. C- 또는 N- 말단 태그 대조적으로,이 센서는 분자 스트레인 게이지로서 행동하고,이 단백질에 걸쳐 전송되는 기계적인 힘을 측정 할 수있는 단백질의 내부 부위에 삽입된다. 프렛-P 사이의 증가 된 거리에서 센서 결과 걸쳐 기계적 장력을 증대공기 감소 FRET 3의 결과. 그 결과, FRET 반비례 인장력에 관한 것이다. 이러한 형광 기반 센서는 초점 접착 단백질 (vinculin 3 talin 4), 세포 골격 단백질 (α-티닌 5), 및 세포 - 세포 접합 단백질을 위해 개발 된 (E-cadherin의 6, 7, VE-cadherin의 8 및 PECAM 8). 이러한 바이오 센서에서 가장 자주 사용되는 잘 특징으로하는 탄성 링커 TSmod라고도하고 거미줄 단백질 flagelliform로부터 유도 된 40 개 아미노산 (GPGGA) (8)의 반복되는 시퀀스로 구성된다. TSmod은 인장력 3/5 PN 1 FRET에 응답하여 선형 탄성 나노 스프링처럼 행동하는 것으로 나타났다. flagelliform의 다른 길이는 동적 R을 변경하는 데 사용할 수 있습니다TSmod FRET 힘 감도 (9)의 플랜지. flagelliform 외에도 스펙 트린은 (HP35라고도 함) (5)와 villin 투구 펩티드 4는 유사한 포스 바이오 센서 (4) 사이의 FRET 쌍 탄성 펩티드로서 사용되어왔다를 반복한다. 마지막으로, 최근의 보고서는 TSmod는 압축력 (10)를 감지하는 데 사용할 수 있다는 것을 보여 주었다. 최근 TSmod 내생 비슷하게 동작 미니 Nesprin2G (도 2C)로 알려진 이전에 개발 된 절두 Nesprin2G 단백질 삽입 이용하여 nucleo - 골격 (LINC) 복합 단백질 Nesprin2G의 링커 힘 센서를 개발 Nesprin-2G (11). LINC 복합체는 핵에 얇은 골격을 연결하는 세포질, 핵의 외부에서 내부로 이끌어 다중 단백질을 포함한다. Nesprin-2G는 구조적 단백질에 결합되는 두세포질과 핵 주변 공간에 태양 단백질 액틴 세포 골격. 우리의 바이오 센서를 사용하여, 우리는 Nesprin-2G는 NIH3T3 섬유 아세포 2 액토 마이 오신에 의존 긴장 될 수 있음을 보여줄 수 있었다. 이것은 그 힘이 바로 핵 LINC 단지에 단백질을 통해 측정 한 처음, 그리고 제어 공학의 핵에 힘의 역할을 이해하는 중요한 도구가 될 가능성이 높습니다. 프로토콜은 아래 Nesprin-을 발현하는 세포의 FRET 화상의 포유 동물 세포에서 Nesprin 장력 센서 (Nesprin-TS)의 발현뿐만 아니라, 수집 및 분석을 포함하여 Nesprin-2G 힘 센서를 사용하는 방법의 상세한 방법을 제공한다 TS. 분광 검출기를 구비 한 반전 된 공 초점 레이저 주사 현미경을 사용하여, 발광 증감을 측정하는 방법을 설명 unmixing 스펙트럼을 이용하여 비율 적 FRET FRET 및 촬상이 제공된다. 출력 이미지가 상대적 비율 적 ...로서 확인하는데 사용될 수있다ntitative 힘 비교. 이 프로토콜은 섬유 아세포 Nesprin-TS의 발현에 집중되는 반면, 세포주 및 일차 전지 모두 포함한 다른 포유 동물 세포에 쉽게 적응할 수있다. 또한, 이미지 수집 및 FRET 분석에 관련된 프로토콜이 용이 다른 단백질에 대해 개발 된 다른 FRET 기반 포스 바이오 센서에 적용될 수있다.

<table><tbody><tr><td>Nesprin-TS DNA</td><td>Addgene</td><td>68127</td><td>Retrieve from https://www.addgene.org/68127/</td></tr><tr><td>Nesprin-HL DNA</td><td>Addgene</td><td>68128</td><td>Retrieve from https://www.addgene.org/68128/</td></tr><tr><td>mTFP1 DNA</td><td>Addgene</td><td>54613</td><td>Retrieve from https://www.addgene.org/54613/</td></tr><tr><td>mVenus DNA</td><td>Addgene</td><td>27793</td><td>Retrieve from https://www.addgene.org/27793/</td></tr><tr><td>TSmod DNA</td><td>Addgene</td><td>26021</td><td>Retrieve from https://www.addgene.org/26021/</td></tr><tr><td>Competent Cells</td><td>Bioline</td><td>BIO-85026</td><td></td></tr><tr><td>Liquid LB Media</td><td>ThermoFisher</td><td>10855001</td><td>https://www.thermofisher.com/order/catalog/product/10855001</td></tr><tr><td>Solid LB Bacterial Culture Plates</td><td>Sigma-Aldrich</td><td>L5667</td><td>http://www.sigmaaldrich.com/catalog/product/sigma/l5667?lang=en&amp;amp;region=US</td></tr><tr><td>Ampicillin</td><td>Sigma</td><td>A9518</td><td></td></tr><tr><td>Spectrophotometer</td><td>Biorad</td><td>273 BR 07335</td><td>SmartSpec Plus</td></tr><tr><td>quartz cuvette</td><td>Biorad</td><td>1702504</td><td>Cuvette for SmartSpec Plus</td></tr><tr><td>DNA isolation kit</td><td>Macherey-Nagel</td><td>740412.5</td><td>NucleoBond Xtra Midi Plus</td></tr><tr><td>6-well cell culture dish</td><td>Falcon-Corning</td><td>353046</td><td>Multiwell 6-well Polystrene Culture Dish</td></tr><tr><td>Dulbecco&#039;s Modified Eagle Medium, (DMEM) cell media</td><td>Gibco</td><td>11995-065</td><td>DMEM(1x)</td></tr><tr><td>Bovine Serum</td><td>Life Technologies</td><td>16170-078</td><td></td></tr><tr><td>reduced serum cell media</td><td>Gibco</td><td>31985-070</td><td>Reduced Serum Medium, &quot;optimem&quot;</td></tr><tr><td>Lipid Carrier Solution</td><td>invitrogen</td><td>11668-019</td><td>Lipid Reagent, &quot;Lipofectamine 2000&quot;</td></tr><tr><td>1.5 mL sterile plastic tube</td><td>Denville</td><td>c2170</td><td></td></tr><tr><td>Trypsin</td><td>Gibco</td><td>25200-056</td><td>0.25% Trypsin-EDTA (1x)</td></tr><tr><td>glass-bottom microscope viewing dish</td><td>In Vitro Scientific</td><td>D35-20-1.5-N</td><td>35 mm Dish with 20 mm Bottom Well #1.5 glass</td></tr><tr><td>Fibronectin</td><td>ThermoFisher</td><td>33016015</td><td>fibronectin human protein, plasma</td></tr><tr><td>Phosphate Buffered Saline (PBS)</td><td>Gibco</td><td>14190-144</td><td>Dulbecco&#039;s Phosphate Buffered Saline</td></tr><tr><td>15 mL sterile centrifuge tube</td><td>Greiner bio-one</td><td>188261</td><td></td></tr><tr><td>swinging rotor centrifuge&amp;nbsp;</td><td>Thermo electron</td><td>Centra CL2</td><td>Swinging rotor thermo electron 236</td></tr><tr><td>cell culture biosafety hood</td><td>Forma Scientific</td><td>1284</td><td></td></tr><tr><td>climate controlled cell culture incubator</td><td>ThermoFisher</td><td>3596</td><td></td></tr><tr><td>inverted LED widefield fluorescent microscope</td><td>Life technologies</td><td>EVOS FL</td><td></td></tr><tr><td>Clear HEPES buffered imaging media</td><td>Molecular Probes</td><td>A14291DJ</td><td></td></tr><tr><td>Fetal bovine Serum</td><td>Life technologies</td><td>10437-028</td><td></td></tr><tr><td>Temperature Controlled-Inverted confocal w/458 and 515 nm laser sources&amp;nbsp;</td><td>Zeiss</td><td>&amp;nbsp;LSM 710-w/spectral META detector</td><td></td></tr><tr><td>Outgrowth Media</td><td>Newengland Biolabs</td><td>B9020s</td><td></td></tr><tr><td>NIH 3T3 Fibroblasts</td><td>ATCC</td><td>CRL-1658</td><td></td></tr></tbody></table>

a protocol for using f&#246;rster resonance energy transfer (fret)-force biosensors to measure mechanical forces across the nuclear linc complex

The LINC complex has been hypothesized to be the critical structure that mediates the transfer of mechanical forces from the cytoskeleton to the nucleus. Nesprin-2G is a key component of the LINC complex that connects the actin cytoskeleton to membrane proteins (SUN domain proteins) in the perinuclear space. These membrane proteins connect to lamins inside the nucleus. Recently, a F&#246;rster Resonance Energy Transfer (FRET)-force probe was cloned into mini-Nesprin-2G (Nesprin-TS (tension sensor)) and used to measure tension across Nesprin-2G in live NIH3T3 fibroblasts. This paper describes the process of using Nesprin-TS to measure LINC complex forces in NIH3T3 fibroblasts. To extract FRET information from Nesprin-TS, an outline of how to spectrally unmix raw spectral images into acceptor and donor fluorescent channels is also presented. Using open-source software (ImageJ), images are pre-processed and transformed into ratiometric images. Finally, FRET data of Nesprin-TS is presented, along with strategies for how to compare data across different experimental groups.

전술 한 프로토콜에 따라, 플라스미드 DNA는 DNA 저장소로부터 취득하고, 대장균에 형질 전환. 센서 DNA를 발현하는 대장균을 LB / 암피실린 플레이트로부터 선택 LB 액체 배지에서 증폭 하였다. 벡터의 증폭에 이어, 플라스미드 DNA는 표준 시판 DNA 분리 키트를 이용 TRIS-EDTA 버퍼로 정제 하였다. 분광 광도계를 사용하여, 정제 된 DNA는 ㎍ / ㎖ (도 1a, 1-2 ...

Watch this Scientific Journal Video about A Protocol for Using FÃ¶rster Resonance Energy Transfer FRET-force Biosensors to Measure Mechanical Forces across the Nuclear LINC Complex at JoVE.com

A Protocol for Using F&#246;rster Resonance Energy Transfer (FRET)-force Biosensors to Measure Mechanical Forces across the Nuclear LINC Complex

A number of FRET-based force biosensors have recently been developed, enabling the protein-specific resolution of intracellular force. In this protocol, we demonstrate how one of these sensors, designed for the linker of the nucleoskeleton-cytoskeleton (LINC) complex protein Nesprin-2G can be used to measure actomyosin forces on the nuclear LINC complex.

포스터 공명 에너지 전달 (FRET) -force의 바이오 센서를 사용하는 프로토콜은 핵 LINC 단지에서 기계의 힘을 측정하는

The LINC complex has been hypothesized to be the critical structure that mediates the transfer of mechanical forces from the cytoskeleton to the nucleus. ...

a-protocol-for-using-frster-resonance-energy-transfer-fret-force

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

10.5K 조회수.  Virginia Commonwealth University. A number of FRET-based force biosensors have recently been developed, enabling the protein-specific resolution of intracellular force. In this protocol, we demonstrate how one of these sensors, designed for the linker of the nucleoskeleton-cytoskeleton (LINC) complex protein Nesprin-2G can be used to measure actomyosin forces on the nuclear LINC complex. 

비디오: A Protocol for Using Förster Resonance Energy Transfer (FRET)-force Biosensors to Measure Mechanical Forces across the Nuclear LINC Complex

High Precision FRET at Single-molecule Level for Biomolecule Structure Determination

A protocol on how to perform high-precision interdye distance measurements using F&#246;rster resonance energy transfer (FRET) at the single-molecule level in multiparameter fluorescence detection (MFD) mode is presented here. MFD maximizes the usage of all &#34;dimensions&#34; of fluorescence to reduce photophysical and experimental artifacts and allows for the measurement of interdye distance with an accuracy up to ~1 &#197; in rigid biomolecules. This method was used to identify three conformational states of the ligand-binding domain of the N-methyl-D-aspartate (NMDA) receptor to explain the activation of the receptor upon ligand binding. When comparing the known crystallographic structures with experimental measurements, they agreed within less than 3 &#197; for more dynamic biomolecules. Gathering a set of distance restraints that covers the entire dimensionality of the biomolecules would make it possible to provide a structural model of dynamic biomolecules.

A protocol for high-precision FRET experiments at the single molecule level is presented here. Additionally, this methodology can be used to identify three conformational states in the ligand-binding domain of the N-methyl-D-aspartate (NMDA) receptor. Determining precise distances is the first step towards building structural models based on FRET experiments.

생체 분자 구조 결정을위한 단일 분자 수준의 고정밀 FRET

A protocol on how to perform high-precision interdye distance measurements using F&#246;rster resonance energy transfer (FRET) at the single-molecule ...

연구

생화학

Multiplexed Single-molecule Force Proteolysis Measurements Using Magnetic Tweezers

The generation and detection of mechanical forces is a ubiquitous aspect of cell physiology, with direct relevance to cancer metastasis1, atherogenesis2 and wound healing3. In each of these examples, cells both exert force on their surroundings and simultaneously enzymatically remodel the extracellular matrix (ECM). The effect of forces on ECM has thus become an area of considerable interest due to its likely biological and medical importance4-7.
	Single molecule techniques such as optical trapping8, atomic force microscopy9, and magnetic tweezers10,11 allow researchers to probe the function of enzymes at a molecular level by exerting forces on individual proteins. Of these techniques, magnetic tweezers (MT) are notable for their low cost and high throughput. MT exert forces in the range of ~1-100 pN and can provide millisecond temporal resolution, qualities that are well matched to the study of enzyme mechanism at the single-molecule level12. Here we report a highly parallelizable MT assay to study the effect of force on the proteolysis of single protein molecules. We present the specific example of the proteolysis of a trimeric collagen peptide by matrix metalloproteinase 1 (MMP-1); however, this assay can be easily adapted to study other substrates and proteases.

In this article we describe the use of magnetic tweezers to study the effect of force on enzymatic proteolysis at the single molecule level in a highly parallelizable manner.

마그네틱 족집게를 사용하여 다중 단일 분자 강제 Proteolysis 측정

The  generation and detection of mechanical forces is a ubiquitous aspect of cell physiology,  with direct relevance to cancer metastasis1, atherogenesis2 ...

생체공학

Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy

In recent years, atomic force microscopy (AFM) based single molecule force spectroscopy (SMFS) extended our understanding of molecular properties and functions. It gave us the opportunity to explore a multiplicity of biophysical mechanisms, e.g., how bacterial adhesins bind to host surface receptors in more detail. Among other factors, the success of SMFS experiments depends on the functional and native immobilization of the biomolecules of interest on solid surfaces and AFM tips. Here, we describe a straightforward protocol for the covalent coupling of proteins to silicon surfaces using silane-PEG-carboxyls and the well-established N-hydroxysuccinimid/1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimid (EDC/NHS) chemistry in order to explore the interaction of pilus-1 adhesin RrgA from the Gram-positive bacterium Streptococcus pneumoniae (S. pneumoniae) with the extracellular matrix protein fibronectin (Fn). Our results show that the surface functionalization leads to a homogenous distribution of Fn on the glass surface and to an appropriate concentration of RrgA on the AFM cantilever tip, apparent by the target value of up to 20% of interaction events during SMFS measurements and revealed that RrgA binds to Fn with a mean force of 52 pN. The protocol can be adjusted to couple via site specific free thiol groups. This results in a predefined protein or molecule orientation and is suitable for other biophysical applications besides the SMFS.

This protocol describes the covalent immobilization of proteins with a heterobifunctional silane coupling agent to silicon-oxide surfaces designed for the atomic force microscopy based single molecule force spectroscopy which is exemplified by the interaction of RrgA (pilus-1 tip adhesin of S. pneumoniae) with fibronectin.

단일 분자 힘 분광학에 대 한 단백질의 화학식 동원 정지

In recent years, atomic force microscopy (AFM) based single molecule force spectroscopy (SMFS) extended our understanding of molecular properties and ...

Investigating Receptor-ligand Systems of the Cellulosome with AFM-based Single-molecule Force Spectroscopy

Cellulosomes are discrete multienzyme complexes used by a subset of anaerobic bacteria and fungi to digest lignocellulosic substrates. Assembly of the enzymes onto the noncatalytic scaffold protein is directed by interactions among a family of related receptor-ligand pairs comprising interacting cohesin and dockerin modules. The extremely strong binding between cohesin and dockerin modules results in dissociation constants in the low picomolar to nanomolar range, which may hamper accurate off-rate measurements with conventional bulk methods. Single-molecule force spectroscopy (SMFS) with the atomic force microscope measures the response of individual biomolecules to force, and in contrast to other single-molecule manipulation methods (i.e.&#160;optical tweezers), is optimal for studying high-affinity receptor-ligand interactions because of its ability to probe the high-force regime (&#62;120 pN). Here we present our complete protocol for studying cellulosomal protein assemblies at the single-molecule level. Using a protein topology derived from the native cellulosome, we worked with enzyme-dockerin and carbohydrate binding module-cohesin (CBM-cohesin) fusion proteins, each with an accessible free thiol group at an engineered cysteine residue. We present our site-specific surface immobilization protocol, along with our measurement and data analysis procedure for obtaining detailed binding parameters for the high-affinity complex. We demonstrate how to quantify single subdomain unfolding forces, complex rupture forces, kinetic off-rates, and potential widths of the binding well. The successful application of these methods in characterizing the cohesin-dockerin interaction responsible for assembly of multidomain cellulolytic complexes is further described.

Cellulosomes are multienzyme complexes designed for digesting cellulose. AFM-based SMFS was used to study the mechanical properties and folding configuration of cellulosome-associated protein assemblies. We present a complete workflow for protein immobilization, data acquisition, and data analysis to study the interactions of individual receptor-ligand complexes involved in cellulosome assembly.

Cellulosomes are discrete multienzyme complexes used by a subset of anaerobic bacteria and fungi to digest lignocellulosic substrates. Assembly of the ...

FIBS-enabled Noninvasive Metabolic Profiling

In the era of computational biology, new high throughput experimental systems are necessary in order to populate and refine models so that they can be validated for predictive purposes. Ideally such systems would be low volume, which precludes sampling and destructive analyses when time course data are to be obtained. What is needed is an in situ monitoring tool which can report the necessary information in real-time and noninvasively. An interesting option is the use of fluorescent, protein-based in vivo biological sensors as reporters of intracellular concentrations. One particular class of in vivo biosensors that has found applications in metabolite quantification is based on F&#246;rster Resonance Energy Transfer (FRET) between two fluorescent proteins connected by a ligand binding domain. FRET integrated biological sensors (FIBS) are constitutively produced within the cell line, they have fast response times and their spectral characteristics change based on the concentration of metabolite within the cell. In this paper, the method for constructing Chinese hamster ovary (CHO) cell lines that constitutively express a FIBS for glucose and glutamine and calibrating the FIBS in vivo in batch cell culture in order to enable future quantification of intracellular metabolite concentration is described. Data from fed-batch CHO cell cultures demonstrates that the FIBS was able in each case to detect the resulting change in the intracellular concentration. Using the fluorescent signal from the FIBS and the previously constructed calibration curve, the intracellular concentration was accurately determined as confirmed by an independent enzymatic assay.

A description of how to calibrate F&#246;rster Resonance Energy Transfer integrated biological sensors (FIBS) for in situ metabolic profiling is presented.&#160;The FIBS can be used to measure intracellular levels of metabolites noninvasively aiding in the development of metabolic models and high throughput screening of bioprocess conditions.

비 침습 대사 프로파일 링에게 FIBS 지원

In the era of computational biology, new high throughput experimental systems are necessary in order to populate and refine models so that they can be ...

Fluorescence Biomembrane Force Probe: Concurrent Quantitation of Receptor-ligand Kinetics and Binding-induced Intracellular Signaling on a Single Cell

Membrane receptor-ligand interactions mediate many cellular functions. Binding kinetics and downstream signaling triggered by these molecular interactions are likely affected by the mechanical environment in which binding and signaling take place. A recent study demonstrated that mechanical force can regulate antigen recognition by and triggering of the T-cell receptor (TCR). This was made possible by a new technology we developed and termed fluorescence biomembrane force probe (fBFP), which combines single-molecule force spectroscopy with fluorescence microscopy. Using an ultra-soft human red blood cell as the sensitive force sensor, a high-speed camera and real-time imaging tracking techniques, the fBFP is of ~1 pN (10-12 N), ~3 nm and ~0.5 msec in force, spatial and temporal resolution. With the fBFP, one can precisely measure single receptor-ligand binding kinetics under force regulation and simultaneously image binding-triggered intracellular calcium signaling on a single live cell. This new technology can be used to study other membrane receptor-ligand interaction and signaling in other cells under mechanical regulation.

We describe a technique for concurrently measuring force-regulated single receptor-ligand binding kinetics and real-time imaging of calcium signaling in a single T lymphocyte.

형광 생체막 포스 프로브 : 하나의 세포에서 수용체 - 리간드 속도론의 동시 정량 및 바인딩에 의한 세포 내 신호

Membrane receptor-ligand interactions mediate many cellular functions. Binding kinetics and downstream signaling triggered by these molecular interactions ...

F&#246;rster Resonance Energy Transfer Measurements in Living Plant Cells

Sensitized emission-based F&#246;rster resonance energy transfer (FRET) experiments are easily done but depend on the microscopic setup. Confocal laser scanning microscopes have become a workhorse for biologists. Commercial systems offer high flexibility in laser power adjustment and detector sensitivity and often combine different detectors to obtain the perfect image. However, the comparison of intensity-based data from different experiments and setups is often impossible due to this flexibility. Biologist-friendly procedures are of advantage and allow for simple and reliable adjustment of laser and detector settings. 
Furthermore, as FRET experiments in living cells are affected by the variability in protein expression and donor-acceptor ratios, protein expression levels must be considered for data evaluation. Described here is a simple protocol for reliable and reproducible FRET measurements, including routines for the estimation of protein expression and adjustment of laser intensity and detector settings. Data evaluation will be performed by calibration with a fluorophore fusion of known FRET efficiency. To improve simplicity, correction factors have been compared that have been obtained in cells and by measuring recombinant fluorescent proteins.

A protocol is provided for setting up a standard confocal laser-scanning microscope for in vivo F&#246;rster resonance energy transfer measurements, followed by data evaluation.

살아있는 식물 세포에서 Förster 공명 에너지 전송 측정

Sensitized emission-based F&#246;rster resonance energy transfer (FRET) experiments are easily done but depend on the microscopic setup. Confocal laser ...

F&#246;rster Resonance Energy Transfer Mapping: A New Methodology to Elucidate Global Structural Features

F&#246;rster resonance energy transfer (FRET) is an established fluorescence-based method used to successfully measure distances in and between biomolecules in vitro as well as within cells. In FRET, the efficiency of energy transfer, measured by changes in fluorescence intensity or lifetime, relates to the distance between two fluorescent molecules or labels. Determination of dynamics and conformational changes from the distances are just some examples of applications of this method to biological systems. Under certain conditions, this methodology can add to and enhance existing X-ray crystal structures by providing information regarding dynamics, flexibility, and adaptation to binding surfaces. We describe the use of FRET and associated distance determinations to elucidate structural properties, through the identification of a binding site or the orientations of dimer subunits. Through judicious choice of labeling sites, and often employment of multiple labeling strategies, we have successfully applied these mapping methods to determine global structural properties in a protein-DNA complex and the SecA-SecYEG protein translocation system. In the SecA-SecYEG system, we have used FRET mapping methods to identify the preprotein-binding site and determine the local conformation of the bound signal sequence region. This study outlines the steps for performing FRET mapping studies, including identification of appropriate labeling sites, discussion of possible labels including non-native amino acid residues, labeling procedures, how to perform measurements, and interpreting the data.

The study details the methodology of FRET mapping including the selection of labeling sites, choice of dyes, acquisition, and data analysis. This methodology is effective at determining binding sites, conformational changes, and dynamic motions in protein systems and is most useful if performed in conjunction with existing 3-D structural information.

Förster 공명 에너지 전달 매핑: 글로벌 구조적 특징을 밝히기 위한 새로운 방법론

F&#246;rster resonance energy transfer (FRET) is an established fluorescence-based method used to successfully measure distances in and between ...

Measurement of Force-Sensitive Protein Dynamics in Living Cells Using a Combination of Fluorescent Techniques

Cells sense and respond to physical cues in their environment by converting mechanical stimuli into biochemically-detectable signals in a process called mechanotransduction. A crucial step in mechanotransduction is the transmission of forces between the external and internal environments. To transmit forces, there must be a sustained, unbroken physical linkage created by a series of protein-protein interactions. For a given protein-protein interaction, mechanical load can either have no effect on the interaction, lead to faster disassociation of the interaction, or even stabilize the interaction. Understanding how molecular load dictates protein turnover in living cells can provide valuable information about the mechanical state of a protein, in turn elucidating its role in mechanotransduction. Existing techniques for measuring force-sensitive protein dynamics either lack direct measurements of protein load or rely on the measurements performed outside of the cellular context. Here, we describe a protocol for the F&#246;rster resonance energy transfer-fluorescence recovery after photobleaching (FRET-FRAP) technique, which enables the measurement of force-sensitive protein dynamics within living cells. This technique is potentially applicable to any FRET-based tension sensor, facilitating the study of force-sensitive protein dynamics in variety of subcellular structures and in different cell types.

Here, we present a protocol for the simultaneous use of F&#246;rster resonance energy transfer-based tension sensors to measure protein load and fluorescence recovery after photobleaching to measure protein dynamics enabling the measurement of force-sensitive protein dynamics within living cells.

살아있는 세포 형광 기술의 조합을 사용 하 여 힘에 민감한 단백질 역학의 측정

Cells sense and respond to physical cues in their environment by converting mechanical stimuli into biochemically-detectable signals in a process called ...

FRET Microscopy for Real-time Monitoring of Signaling Events in Live Cells Using Unimolecular Biosensors

F&ouml;rster resonance energy transfer (FRET) microscopy continues to gain increasing interest as a technique for real-time monitoring of biochemical and signaling events in live cells and tissues. Compared to classical biochemical methods, this novel technology is characterized by high temporal and spatial resolution. FRET experiments use various genetically-encoded biosensors which can be expressed and imaged over time in situ or in vivo1-2. Typical biosensors can either report protein-protein interactions by measuring FRET between a fluorophore-tagged pair of proteins or conformational changes in a single protein which harbors donor and acceptor fluorophores interconnected with a binding moiety for a molecule of interest3-4. Bimolecular biosensors for protein-protein interactions include, for example, constructs designed to monitor G-protein activation in cells5, while the unimolecular sensors measuring conformational changes are widely used to image second messengers such as calcium6, cAMP7-8, inositol phosphates9 and cGMP10-11. Here we describe how to build a customized epifluorescence FRET imaging system from single commercially available components and how to control the whole setup using the Micro-Manager freeware. This simple but powerful instrument is designed for routine or more sophisticated FRET measurements in live cells. Acquired images are processed using self-written plug-ins to visualize changes in FRET ratio in real-time during any experiments before being stored in a graphics format compatible with the build-in ImageJ freeware used for subsequent data analysis. This low-cost system is characterized by high flexibility and can be successfully used to monitor various biochemical events and signaling molecules by a plethora of available FRET biosensors in live cells and tissues. As an example, we demonstrate how to use this imaging system to perform real-time monitoring of cAMP in live 293A cells upon stimulation with a &beta;-adrenergic receptor agonist and blocker.

F&#246;rster resonance energy transfer (FRET) microscopy is a powerful technique for real-time monitoring of signaling events in live cells using various biosensors as reporters. Here we describe how to build a customized epifluorescence FRET imaging system from commercially available components and how to use it for FRET experiments.

Unimolecular 바이오 센서를 사용하여 라이브 세포에서 이벤트를 신호의 실시간 모니터링을위한 현미경을 안달

F&ouml;rster resonance energy transfer (FRET) microscopy  continues to gain increasing interest as a technique for real-time monitoring  of biochemical ...