http://dx.doi.org/10.1152/ajpendo.00176.2014">
 

Document Type

Journal Article

Department/Unit

Department of Biology

Title

Differential effects of c-Src and c-Yes on the endocytic vesicle-mediated trafficking events at the Sertoli cell blood-testis barrier: An in vitro study

Language

English

Abstract

© 2014 the American Physiological Society. The blood-testis barrier (BTB) is one of the tightest blood-tissue barriers in the mammalian body. However, it undergoes cyclic restructuring during the epithelial cycle of spermatogenesis in which the “old” BTB located above the preleptotene spermatocytes being transported across the immunological barrier is “disassembled,” whereas the “new” BTB found behind these germ cells is rapidly “reassembled,” i.e., mediated by endocytic vesicle-mediated protein trafficking events. Thus, the immunological barrier is maintained when preleptotene spermatocytes connected in clones via intercellular bridges are transported across the BTB. Yet the underlying mechanism(s) in particular the involving regulatory molecules that coordinate these events remains unknown. We hypothesized that c-Src and c-Yes might work in contrasting roles in endocytic vesicle-mediated trafficking, serving as molecular switches, to effectively disassemble and reassemble the old and the new BTB, respectively, to facilitate preleptotene spermatocyte transport across the BTB. Following siRNA-mediated specific knockdown of c-Src or c-Yes in Sertoli cells, we utilized biochemical assays to assess the changes in protein endocytosis, recycling, degradation and phagocytosis. c-Yes was found to promote endocytosed integral membrane BTB proteins to the pathway of transcytosis and recycling so that internalized proteins could be effectively used to assemble new BTB from the disassembling old BTB, whereas c-Src promotes endocytosed Sertoli cell BTB proteins to endosome-mediated protein degradation for the degeneration of the old BTB. By using fluorescence beads mimicking apoptotic germ cells, Sertoli cells were found to engulf beads via c-Src-mediated phagocytosis. A hypothetical model that serves as the framework for future investigation is thus proposed.

Keywords

Blood-testis barrier, c-Src, c-Yes, Ectoplasmic specialization, Endosome, Recycling, Seminiferous epithelial cycle, Spermatogenesis, Testis, Tight junction, Transcytosis

Publication Date

2014

Source Publication Title

AJP - Endocrinology and Metabolism

Volume

307

Issue

7

Start Page

E553

End Page

E562

Publisher

American Physiological Society

ISSN (print)

01931849

ISSN (electronic)

15221555

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