title: Testicular proteins associated with the germ cell-marker, TEX101: involvement of cellubrevin in TEX101-trafficking to the cell surface during spermatogenesis.
abstract: Recently, we identified a cell-surface marker protein, TEX101, that is unique to male and female germ cells. On/off switching of TEX101 expression in germ cells is closely linked to the kinetics of gametogenesis. In the present study, we isolated testicular proteins by immunoprecipitation with anti-TEX101 antibody and identified the proteins using liquid chromatography/tandem mass spectrometry. Of three proteins identified (annexin 2, ly6k, and cellubrevin), a biochemical association between TEX101 and cellubrevin was confirmed by immunoprecipitation-Western blotting experiments. Immunohistochemistry using a cellubrevin-specific antibody indicated that the molecule is abundant on spermatocytes and early-stage spermatids, whereas negligible amounts are found in Sertoli cells, spermatogonia, spermatozoa, and late-stage spermatids. Most of the intracellular cellubrevin appeared to be juxtaposed with intracellular TEX101, and membrane-associated cellubrevin was docked near TEX101-positive plasma membranes on the cytoplasmic side. This close association was never observed on the outer surface of the plasma membrane. From these results we concluded that cellubrevin-dependent membrane trafficking is involved in TEX101-transport to the surface of male germ cells.
authors: Institute for Environmental and Gender-Specific Medicine, Juntendo University Graduate School of Medicine, Urayasu-City 279-0021, Japan.
authors: Hiroki
authors: H
authors: Tsukamoto
authors: Hiroshi
authors: H
authors: Yoshitake
authors: Miki
authors: M
authors: Mori
authors: Mitsuaki
authors: M
authors: Yanagida
authors: Kenji
authors: K
authors: Takamori
authors: Hideoki
authors: H
authors: Ogawa
authors: Toshihiro
authors: T
authors: Takizawa
authors: Yoshihiko
authors: Y
authors: Araki