NCBI Summary:
The protein encoded by this gene belongs to the Rab family of the small GTPase superfamily. It is associated with both constitutive and regulated secretory pathways, and may be involved in protein transport. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2011]
General function
Comment
Cellular localization
Comment
Ovarian function
Early embryo development
Comment
Two pathways regulate cortical granule translocation to prevent polyspermy in mouse oocytes. Cheeseman LP et al. (2016) An egg must be fertilized by a single sperm only. To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules. These translocate from the oocyte's centre to the plasma membrane during meiosis. However, very little is known about the mechanism of cortical granule translocation. Here we investigate cortical granule transport and dynamics in live mammalian oocytes by using Rab27a as a marker. We show that two separate mechanisms drive their transport: myosin Va-dependent movement along actin filaments, and an unexpected vesicle hitchhiking mechanism by which cortical granules bind to Rab11a vesicles powered by myosin Vb. Inhibiting cortical granule translocation severely impaired the block to sperm entry, suggesting that translocation defects could contribute to miscarriages that are caused by polyspermy.//////////////////