Activation of ROCK and MLCK tunes regional stress fiber formation and mechanics via preferential myosin light chain phosphorylation.

摘要: The assembly and mechanics of actomyosin stress fibers (SFs) depend on myosin regulatory light chain (RLC) phosphorylation, which is driven by kinase (MLCK) Rho-associated (ROCK). Although previous work suggests that MLCK ROCK control distinct pools cellular SFs, it remains unclear how these kinases differ in their regulation RLC phosphorylation or influences individual SF mechanics. Here, we combine genetic approaches with biophysical tools to explore relationships between activity, localization, We show graded overexpression increases monophosphorylation (p-RLC) a manner this p-RLC localizes peripheral SFs. Conversely, preferentially diphosphorylation (pp-RLC), pp-RLC localizing central Interrogation single SFs subcellular laser ablation reveals quantitatively regulate the viscoelastic properties respectively. effects single-SF may be correspondingly phenocopied mono- diphosphomimetic mutants. Our results point model through RLC, offering new quantitative connections viscoelasticity.