PIK3C3/VPS34 controls Sertoli cell polarity in the mouse testis through the stabilization of the actin cytoskeleton

ABSTRACT: Sertoli cells are highly polarized testicular cells that provide a nurturing environment for germ cell development and maturation during spermatogenesis. The Class III PI3K, PIK3C3/VPS34 plays key roles in endosomal membrane traffic and macroautophagy in various cell types; however, its role in Sertoli cells remains unclear. Here, we generated a mouse line in which Pik3c3 was specifically deleted in Sertoli cells (cKO) and found that after one round of normal spermatogenesis, the cKO mice quickly became infertile and showed disruption of Sertoli cell polarity, loss of germ cells and impaired spermiogenesis. Subsequent proteomics and phosphoproteomics analyses enriched the F-actin cytoskeleton network involved in the disorganized Sertoli-cell structure in cKO testis, and showed significantly increased expression of the F-actin negative regulator SCIN and reduced phosphorylation of the α-tubulin deacetylase HDAC6. Our results further demonstrated that the accumulation of SCIN in cKO Sertoli cells caused the disassembly of the F-actin cytoskeleton, which was related to the failure of SCIN degradation through the autophagy-lysosome pathway. Additionally, we found that the phosphorylation of HDAC6 at site S59 by PIK3C3 was essential for its degradation through the ubiquitin-proteasome pathway. As a result, the HDAC6 that accumulated in cKO Sertoli cells deacetylated SCIN at site K189 and led to a disorganized F-actin cytoskeleton. Taken together, our findings elucidate the indispensable role of PIK3C3 in maintaining Sertoli cell polarity and reveal a new mechanism in which both its protein kinase activity and its regulation of autophagy are required for the stabilization of the actin cytoskeleton.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Testis

SUBMITTER: 克瀚 王  

LAB HEAD: Jing Li

PROVIDER: PXD036240 | Pride | 2024-08-09

REPOSITORIES: Pride