Myosin Va modulates FAK localization and trafficking

Focal adhesion kinase (FAK) is essential for cell adhesion and migration, and its localization within the cell is tightly regulated. In this study, we explored the interaction between FAK and the motor protein Myosin Va (Myo Va) in fibroblasts and its role in FAK trafficking and focal adhesion (FA) organization. Using co-immunoprecipitation, super-resolution microscopy, and image analysis in NIH-3T3 fibroblasts, we demonstrated that FAK interacts with Myo Va in both cytoplasmic and nuclear compartments. Pharmacological inhibition of FAK catalytic activity resulted in decreased association with Myo Va, altered subcellular distribution of FAK, and reduced both the size and number of focal adhesions. Additionally, the knockdown of Myo Va resulted in FAK accumulation in the nuclear and focal adhesion compartments, along with disrupted orientation of focal adhesions, suggesting that Myo Va plays a role in regulating FAK subcellular distribution and the organization of focal adhesions. These findings indicate that Myo Va contributes to the spatial regulation of FAK in fibroblasts, promoting its proper localization at adhesion sites and facilitating its nucleocytoplasmic shuttling transport. Our data reveal a previously unrecognized mechanism for FAK regulation involving its interaction with a myosin molecular motor.