Novel clathrin/actin-based endocytic machinery associated with junction turnover in the seminiferous epithelium

Tubulobulbar complexes are elaborate clathrin/actin related structures that form at sites of intercellular attachment in the seminiferous epithelium of the mammalian testis. Here we summarize what is currently known about the morphology and molecular composition of these structures and review evidence that the structures internalize intercellular junctions both at apical sites of Sertoli cell attachment to spermatids, and at basal sites where Sertoli cells form the blood-testis barrier. We present updated models of the sperm release and spermatocyte translocation mechanisms that incorporate tubulobulbar complexes into their designs.