Clathrin-mediated endocytosis is essential for the selective degradation of maternal membrane proteins and preimplantation development

ABSTRACT Fertilization triggers significant cellular remodeling through the oocyte-to-embryo transition. In this transition, ubiquitin-proteasome system and autophagy are essential for degradation of maternal components; however, significance cell surface components remains unknown. study, we show that multiple plasma membrane proteins, such as glycine transporter GlyT1a, selectively internalized from to endosomes in mouse embryos by late two-cell stage then transported lysosomes at later stages. During process, large amounts ubiquitylated proteins accumulated on endosomes. Furthermore, GlyT1a with mutations potential ubiquitylation sites was delayed, suggesting may be involved degradation. The clathrin inhibitor blocked internalization. Strikingly, protein kinase C (PKC) activator triggered heterochronic internalization GlyT1a; PKC markedly endocytosis. Lastly, inhibition completely embryogenesis inhibited division after four-cell stage. These findings demonstrate PKC-dependent clathrin-mediated endocytosis is selective during transition early embryogenesis.