Vinexin family (SORBS) proteins regulate mechanotransduction in mesenchymal stem cells

The stiffness of extracellular matrix (ECM) directs the differentiation of mesenchymal stem cells (MSCs) through the transcriptional co-activators Yes-associated protein (YAP) and transcriptional coactivator with a PDZ-binding motif (TAZ). Although a recent study revealed the involvement of vinexin α and CAP (c-Cbl-associated proteins), two of vinexin (SORBS) family proteins that bind to vinculin, in mechanosensing, it is still unclear whether these proteins regulate mechanotransduction and differentiation of MSCs. In the present study, we show that both vinexin α and CAP are necessary for the association of vinculin with the cytoskeleton and the promotion of YAP/TAZ nuclear localization in MSCs grown on rigid substrates. Furthermore, CAP is involved in the MSC differentiation in a stiffness-dependent manner, whereas vinexin depletion suppresses adipocyte differentiation independently of YAP/TAZ. These observations reveal a critical role of vinexin α and CAP in mechanotransduction and MSC differentiation.