Rab10 regulates cortical granule translocation and ZP2 dynamics for zona pellucida function during oocyte maturation.

Successful fertilization is important for early embryo development and offspring generation. Cortical granules which are formed in the cytoplasm, are transported to the cortex to avoid polyspermy which prevent sperm penetration into oocytes. The underlying mechanism is still largely unknown. In present study, we identified that GTPase Rab10-mediated vesicles played a pivotal role on actin dynamics, which regulated cortical granule transport and ZP2 function in mouse and porcine oocytes. We found that Rab10 accumulated at the oocyte cortex and modulated RhoA pathway to control actin dynamics, and disrupting the functions of Rab10 affected myosin Va expression, which impaired cortical granule movement to the cortex, causing insufficient supply of cortical granules contents and weakened zona pellucida modification. Besides, overexpression of GDP-bound Rab10 led to ZP2 down-regulation and accumulation at the cortex, which affected zona pellucida reaction. Taken together, our findings demonstrated that Rab10 regulated RhoA pathway for actin dynamics and myosin Va complex for cortical granule-based cortical reaction, and Rab10-ZP2 complex contributes to ZP2 supply for zona pellucida reaction.