Proteolytic cleavage of the cell surface protein p160 is required for detachment of the fertilization envelope in the sea urchin
Abstract
Sea urchin eggs secrete a serine protease activity, CGSP1, at fertilization that is essential for the block to polyspermy. Several targets of this proteolytic activity on the plasma membrane were identified here using a cell surface biotinylation approach. Amino acid microsequencing of one of these proteins led to the identification of a 4.75-kb cDNA clone from a Strongylocentrotus purpuratus ovary cDNA library that encodes a 160-kDa protein called p160. This protein contains five CUB domains and a putative transmembrane domain suggesting that p160 is an integral membrane protein with protein-protein interaction motifs facing the extracellular matrix of the egg. Whole-mount immunolocalization studies demonstrate that p160 is on the surface of the egg, enriched at the tips of microvilli. The protein is removed at fertilization in a protease-dependent manner, and functional assays suggest that p160 serves to link the plasma membrane to the vitelline layer until fertilization. Thus, p160 is a key candidate for a vitelline-layer linker protein, the selective proteolysis of which functions in the block to polyspermy in the sea urchin egg.
References
Citations
Related Concepts
Related Feeds
Adhesion Molecules in Health and Disease
Cell adhesion molecules are a subset of cell adhesion proteins located on the cell surface involved in binding with other cells or with the extracellular matrix in the process called cell adhesion. In essence, cell adhesion molecules help cells stick to each other and to their surroundings. Cell adhesion is a crucial component in maintaining tissue structure and function. Discover the latest research on adhesion molecule and their role in health and disease here.