The regulated expression of c-IAP1 and c-IAP2 during the rat seminiferous epithelial cycle plays a role in the protection of germ cells from Fas-mediated apoptosis

: Wang Y, Suominen JS, Parvinen M, Rivero-Muller A, Kiiveri S, Heikinheimo M, Robbins I, Toppari J

: 2005

: Molecular and Cellular Endocrinology

: Molecular and cellular endocrinology

: Mol Cell Endocrinol

: 245

: 1-2

: 111

: 20

: 10

: 0303-7207

DOI: https://doi.org/10.1016/j.mce.2005.11.004

The inhibitor of apoptosis proteins, c-IAP1 and c-IAP2, are highly expressed in rat testis and potentially play a regulatory role in testicular apoptosis. To better understand their functions during spermatogenesis, we have analyzed their spatio-temporal distribution in rat testis, how their expression is controlled by the paracrine stem-cell factor (SCF) and how they affect Fas-mediated apoptosis. Both c-IAP1 and c-IAP2 showed cycles of transcriptional expression, throughout the seminiferous epithelial cycle. c-IAP1 protein showed a diffuse nuclear distribution in type B spermatogonia, preleptotene, leptotene, and zygotene spermatocytes. In pachytene spermatocytes, c-IAP1 colocalized with SUMO-1 in the XY-body. c-IAP2 protein was cytoplasmic in spermatocytes, from stage VI pachytene onwards, round spermatids, elongated spermatids and Leydig cells. Its expression was upregulated by SCF. Inhibition of IAP activity resulted in a greater sensitivity of germ cells to Fas-mediated apoptosis. These results suggest an important role for IAPs in the regulation of spermatogenic apoptosis.