αB-Crystallin interacts and attenuates the tyrosine phosphatase activity of Shp2 in cardiomyocytes under mechanical stress.

The small heat shock protein αB-Crystallin (CryAB, HspB5) and SH2 domain-containing tyrosine phosphatase 2 (Shp2) are important molecules in heart response to pathophysiological stress. Here we show that CryAB interacts with and potentially regulates Shp2 catalytic activity in stretched cardiomyocytes. Such an interaction requires CryAB oligomer to attenuate Shp2 activation.

αB-crystallin interacts with and prevents stress-activated proteolysis of focal adhesion kinase by calpain in cardiomyocytes.

Focal adhesion kinase (FAK) contributes to cellular homeostasis under stress conditions. Here we show that αB-crystallin interacts with and confers protection to FAK against calpain-mediated proteolysis in cardiomyocytes. A hydrophobic patch mapped between helices 1 and 4 of the FAK FAT domain was found to bind to the β4-β8 groove of αB-crystallin.

FERM domain interaction with myosin negatively regulates FAK in cardiomyocyte hypertrophy.

Focal adhesion kinase (FAK) regulates cellular processes that affect several aspects of development and disease. The FAK N-terminal FERM (4.1 protein-ezrin-radixin-moesin homology) domain, a compact clover-leaf structure, binds partner proteins and mediates intramolecular regulatory interactions.