Spatial proximity of proteins surrounding zyxin under force-bearing conditions |
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Authors: | Joleen S Cheah Kyle A Jacobs Tzu Wei Lai Reca Caballelo Jacqueline L Yee Shuji Ueda Volkmar Heinrich Soichiro Yamada |
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Institution: | Nagoya University;aBiomedical Engineering Department, University of California Davis, Davis, CA 95616;bGraduate School of Agricultural Science, Kobe University, Kobe, Japan 657;cBiosciences Program, Stanford University, Stanford, CA 94305 |
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Abstract: | Sensing physical forces is a critical first step in mechano-transduction of cells. Zyxin, a LIM domain-containing protein, is recruited to force-bearing actin filaments and is thought to repair and strengthen them. Yet, the precise force-induced protein interactions surrounding zyxin remain unclear. Using BioID analysis, we identified proximal proteins surrounding zyxin under normal and force-bearing conditions by label-free mass spectrometry analysis. Under force-bearing conditions, increased biotinylation of α-actinin 1, α-actinin 4, and AFAP1 were detected, and these proteins accumulated along force-bearing actin fibers independently from zyxin, albeit at a lower intensity than zyxin. VASP also accumulated along force-bearing actin fibers in a zyxin-dependent manner, but the biotinylation of VASP remained constant regardless of force, supporting the model of a free zyxin–VASP complex in the cytoplasm being corecruited to tensed actin fibers. In addition, ARHGAP42, a RhoA GAP, was also identified as a proximal protein of zyxin and colocalized with zyxin along contractile actin bundles. The overexpression of ARHGAP42 reduced the rate of small wound closure, a zyxin-dependent process. These results demonstrate that the application of proximal biotinylation can resolve the proximity and composition of protein complexes as a function of force, which had not been possible with traditional biochemical analysis. |
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