Phosphorylation and turnover of paxillin in focal contacts is controlled by force and defines the dynamic state of the adhesion site

Abstract

Micro-environmental clues are critical to cell behavior. One of the key elements of migration is the generation and response to forces. Up to now there is no definitive concept on how the generation and responses to cellular forces influence cell behavior. Here, we show that phosphorylation of paxillin is a crucial event in the response to exogenous forces. Application of force induced growth of adhesion sites and this phenomenon was accompanied by a downregulation of Src family kinase activity, which in turn led to a decrease in the phosphorylation of paxillin at the tyrosine residues Y31 and Y118. The force-dependent growth of adhesion sites is mediated by a decrease in the turnover-rate of paxillin in focal contacts. This turnover critically depended on the phosphorylation state of paxillin at Y31/118. Paxillin is an important regulator in the control of the aggregate state of the whole adhesion site since the turnover of other adhesion site proteins such as vinculin is influenced by the phosphorylation state of paxillin as well. Taken together these data suggest that SFK dependent phosphorylation of paxillin is a crucial event in the regulation of adhesion site function in response to force.

Mechanosensitivity of integrin adhesion complexes: role of the consensus adhesome

“…In agreement with this, cyclic stretch induced phosphorylation of paxillin and paxillin-dependent endothelial cell permeability [68]. However, shear forces have been shown to reduce paxillin phosphorylation and turnover [69]. Therefore, different types of force may differentially regulate paxillin phosphorylation and its mechanosensing activity.…”

Cellular Mechanotransduction: From Tension to Function

“…The phosphorylation of tyrosine and serine residues in LIM domain has been detected on rigid substrates. Nevertheless, it is still unclear whether these rounds of phosphorylation account for paxillin mechanosensing activity ( Bae et al, 2014 ; Qin et al, 2015 ).…”

“…So far, the definition of cellular mechanosensor has been applied to a number of molecules – mainly proteins – displaying a status change in response to mechanical stimulation. The nature and the degree of the change imposed by mechanical cues can vary significantly and post-translational modifications ( Sawada et al, 2006 ; Dong et al, 2009 ; Hayakawa et al, 2011 ; Swift et al, 2013 ; Guilluy et al, 2014 ; Qin et al, 2015 ; Sathe et al, 2016 ; Lachowski et al, 2018 ), intracellular shuttling ( Gumbiner, 1995 ; Gottardi et al, 1996 ; Huber et al, 1996 ; Lewis et al, 1996 ; Orsulic and Peifer, 1996 ; Nix and Beckerle, 1997 ; Dupont et al, 2011 ), protein unfolding ( del Rio et al, 2009 ), the creation of novel interactions ( Humphries et al, 2007 ) are considered as positive signatures of mechanical responsiveness. All these responses can be found during the transmission of mechanical signals from the ECM to the nucleus, a molecular process collectively known as mechanotransduction.…”

Gastrin stimulates pancreatic cancer cell directional migration by activating the Gα12/13–RhoA–ROCK signaling pathway

“…During the formation of focal adhesion, paxillin is an adapter protein that functions in an important scaffolding role by recruiting structural and signaling molecules when it is phosphorylated on specific Tyr and Ser residues 18 , 35 , 36 . Among these residues, Tyr31 and Tyr118 are the most important 18 .…”