Moreover, we have recently shown that the ectodomains of CD155 and nectin-3 express strong affinity to each other (see note added in proof). Nectin and E-cadherin interact through proteins associated with their cytoplasmic domains and are thought to act cooperatively in the formation of adherens junctions. This novel nec-tin adhesion unit is linked to the actin cytoskeleton by interaction of its cytoplasmic domain with the F actin-binding protein afadin.
In mammalian testis, Sertoli cells create a unique seminiferous epithelium that cultivates differentiating germ cells during the process of spermatogenesis. Formation and maturation of spermatids depends on an intricate interplay between the Sertoli cell and the developing gamete. Sertoli cells maintain two types of specialized cell-cell junctions through structures termed ectoplasmic specializations. They form between Sertoli cells near the base of the epithelium (basal ectoplasmic specializations) and between Sertoli cells and heads of elongated spermatids (apical ectoplasmic specializations). Ectoplasmic specializations are characterized by hexagonal arrays of actin filaments intimately linked to both the cell membrane and endoplasmic reticulum (ER) cisternae of the Sertoli cell.