Wolfenson, HaguyMeacci, GiovanniLiu, ShuaiminStachowiak, Matthew R.Iskratsch, ThomasGhassemi, SabaRoca-Cusachs Soulere, PereShaughnessy, Ben O'Hone, JamesSheetz, Michael P.2019-02-082019-02-0820161465-7392https://hdl.handle.net/2445/128079Cells test the rigidity of the extracellular matrix by applying forces to it through integrin adhesions. Recent measurements show that these forces are applied by local micrometre-scale contractions, but how contraction force is regulated by rigidity is unknown. Here we performed high temporal- and spatial-resolution tracking of contractile forces by plating cells on sub-micrometre elastomeric pillars. We found that actomyosin-based sarcomere-like contractile units (CUs) simultaneously moved opposing pillars in net steps of ∼2.5 nm, independent of rigidity. What correlated with rigidity was the number of steps taken to reach a force level that activated recruitment of α-actinin to the CUs. When we removed actomyosin restriction by depleting tropomyosin 2.1, we observed larger steps and higher forces that resulted in aberrant rigidity sensing and growth of non-transformed cells on soft matrices. Thus, we conclude that tropomyosin 2.1 acts as a suppressor of growth on soft matrices by supporting proper rigidity sensing.10 p.application/pdfeng(c) Wolfenson, Haguy et al., 2016Matriu extracel·lularExtracellular matrixinfo:eu-repo/semantics/article6603672019-02-08info:eu-repo/semantics/openAccess26619148