Unconventional myosin-VI
cytoplasm
Myosin VI is a mediator of the p53-dependent cell survival pathway.
Myosin VI is an unconventional motor protein, and its mutation is responsible for the familiar conditions sensorineural deafness and hypertrophic cardiomyopathy. Myosin VI is found to play a key role in the protein trafficking and homeostasis of the Golgi complex. However, very little is known about how myosin VI is regulated and whether myosin VI has a function in the DNA damage response. Here, we found that myosin VI is regulated by DNA damage in a p53-dependent manner and possesses a novel function in the p53-dependent prosurvival pathway. Specifically, we show that myosin VI is induced by p53 and DNA damage in a p53-dependent manner. We found that p53 directly binds to, and activates, the promoter of the myosin VI gene. We also show that the intracellular localization of myosin VI is substantially altered by p53 and DNA damage in a p53-dependent manner such that the pool of myosin VI in endocytic vesicles, membrane ruffles, and cytosol migrates to the Golgi complex, perinuclear membrane, and nucleus. Furthermore, we show that knockdown of myosin VI attenuates activation of p53 and impairs Golgi complex integrity, which makes myosin VI-deficient cells susceptible to apoptosis upon DNA damage. Taken together, we found a novel function for p53 in the maintenance of Golgi complex integrity and for myosin VI in the p53-dependent prosurvival pathway.