cAMP perturbs inter-Sertoli tight junction permeability barrier in vitro via its effect on proteasome-sensitive ubiquitination of occludin.

摘要: Throughout spermatogenesis, inter-Sertoli tight junctions (TJs) that constitute the blood-testis barrier must be disassembled and reassembled to permit timely movement of preleptotene leptotene spermatocytes from basal adluminal compartment seminiferous epithelium. However, mechanism participating molecules regulate bioavailability TJ proteins are entirely unknown. Using Sertoli cell culture, it was shown there an increase in occludin level, concomitant with a reduction E3 ubiquitin ligase, Itch, at time when TJs were assembled. By co-immunoprecipitation, associate Itch TJs. A novel interaction between UBC4 (an ubiquitin-conjugating enzyme) identified. When disrupted by dibutyryl-cAMP (db-cAMP), protein levels along significant endogenous detected. These results seemingly suggest on is potentially involved regulating dynamics. Addition proteasome inhibitor, MG-132, into cells cultured db-cAMP blocked db-cAMP-induced loss vitro. Accumulations ubiquitin-conjugated Itch-conjugated detected presence both MG-132 db-cAMP. prevented disruption altering rate degradation. Taken collectively, reported herein support notion mediated induction expression, which turn triggered ubiquitination resulting disruption. © 2004 Wiley-Liss, Inc.