NCBI Summary:
This gene encodes an E3 ubiquitin ligase protein that contains a RING finger, a motif present in a variety of functionally distinct proteins and known to be involved in protein-DNA and protein-protein interactions. The protein is involved in DNA double-strand break (DSB) repair. Mutations in this gene result in Riddle syndrome. [provided by RefSeq, Sep 2011]
General function
Cell cycle regulation
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Early embryo development
Comment
Expression regulated by
Comment
Ovarian localization
Oocyte
Comment
Fertilization-induced K63-linked ubiquitylation mediates clearance of maternal membrane proteins. Sato M 2014 et al.
In Caenorhabditis elegans, fertilization triggers endocytosis and rapid turnover of maternal surface membrane proteins in lysosomes, although the precise mechanism of this inducible endocytosis is unknown. We found that high levels of K63-linked ubiquitin chains transiently accumulated on endosomes upon fertilization. Endocytosis and the endosomal accumulation of ubiquitin were both regulated downstream of the anaphase-promoting complex, which drives the oocyte's meiotic cell cycle after fertilization. The clearance of maternal membrane proteins and the accumulation of K63-linked ubiquitin on endosomes depended on UBC-13 and UEV-1, which function as an E2 complex that specifically mediates chain elongation of K63-linked polyubiquitin. CAV-1-GFP, an endocytic cargo protein, was modified with K63-linked polyubiquitin in a UBC-13/UEV-1-dependent manner. In ubc-13 or uev-1 mutants, CAV-1-GFP and other membrane proteins were internalized from the plasma membrane normally after fertilization. However, they were not efficiently targeted to the multivesicular body (MVB) pathway but recycled to the cell surface. Our results suggest that UBC-13-dependent K63-linked ubiquitylation is required for proper MVB sorting rather than for internalization. These results also demonstrate a developmentally controlled function of K63-linked ubiquitylation.
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