The focal adhesion protein talin is a mechanically gated A-kinase anchoring protein.

Kang, Mingu ORCID: 0000-0001-6574-6661, Otani, Yasumi ORCID: 0009-0008-6049-1135, Guo, Yanyu ORCID: 0000-0001-6368-9237, Yan, Jie ORCID: 0000-0002-8555-7291, Goult, Benjamin T ORCID: 0000-0002-3438-2807 and Howe, Alan K ORCID: 0000-0003-2511-5288 (2024) The focal adhesion protein talin is a mechanically gated A-kinase anchoring protein. Proceedings of the National Academy of Sciences of the United States of America, 121 (13). e2314947121-.

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Abstract

Protein kinase A (PKA) is a ubiquitous, promiscuous kinase whose activity is specified through subcellular localization mediated by A-kinase anchoring proteins (AKAPs). PKA has complex roles as both an effector and a regulator of integrin-mediated cell adhesion to extracellular matrix (ECM). Recent observations demonstrate that PKA is an active component of focal adhesions (FA), suggesting the existence of one or more FA AKAPs. Using a promiscuous biotin ligase fused to PKA type-IIα regulatory (RIIα) subunits and subcellular fractionation, we identify the archetypal FA protein talin1 as an AKAP. Talin is a large, mechanosensitive scaffold that directly links integrins to actin filaments and promotes FA assembly by recruiting additional components in a force-dependent manner. The rod region of talin1 consists of 62 α-helices bundled into 13 rod domains, R1 to R13. Direct binding assays and NMR spectroscopy identify helix41 in the R9 subdomain of talin as the PKA binding site. PKA binding to helix41 requires unfolding of the R9 domain, which requires the linker region between R9 and R10. Experiments with single molecules and in cells manipulated to alter actomyosin contractility demonstrate that the PKA-talin interaction is regulated by mechanical force across the talin molecule. Finally, talin mutations that disrupt PKA binding also decrease levels of total and phosphorylated PKA RII subunits as well as phosphorylation of VASP, a known PKA substrate, within FA. These observations identify a mechanically gated anchoring protein for PKA, a force-dependent binding partner for talin1, and a potential pathway for adhesion-associated mechanotransduction.

Item Type:	Article
Uncontrolled Keywords:	Focal Adhesions, Cyclic AMP-Dependent Protein Kinases, Talin, Integrins, Cell Adhesion, Mechanotransduction, Cellular, Protein Binding, A Kinase Anchor Proteins
Divisions:	Faculty of Health and Life Sciences Faculty of Health and Life Sciences > Institute of Systems, Molecular and Integrative Biology
Depositing User:	Symplectic Admin
Date Deposited:	25 Mar 2024 15:23
Last Modified:	10 Apr 2024 10:31
DOI:	10.1073/pnas.2314947121
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3179887