title: Polarity protein Crumbs homolog-3 (CRB3) regulates ectoplasmic specialization dynamics through its action on F-actin organization in Sertoli cells.
abstract: Crumbs homolog 3 (or Crumbs3, CRB3) is a polarity protein expressed by Sertoli and germ cells at the basal compartment in the seminiferous epithelium. CRB3 also expressed at the blood-testis barrier (BTB), co-localized with F-actin, TJ proteins occludin/ZO-1 and basal ES (ectoplasmic specialization) proteins N-cadherin/β-catenin at stages IV-VII only. The binding partners of CRB3 in the testis were the branched actin polymerization protein Arp3, and the barbed end-capping and bundling protein Eps8, illustrating its possible role in actin organization. CRB3 knockdown (KD) by RNAi in Sertoli cells with an established tight junction (TJ)-permeability barrier perturbed the TJ-barrier via changes in the distribution of TJ- and basal ES-proteins at the cell-cell interface. These changes were the result of CRB3 KD-induced re-organization of actin microfilaments, in which actin microfilaments were truncated, and extensively branched, thereby destabilizing F-actin-based adhesion protein complexes at the BTB. Using Polyplus in vivo-jetPEI as a transfection medium with high efficiency for CRB3 KD in the testis, the CRB3 KD testes displayed defects in spermatid and phagosome transport, and also spermatid polarity due to a disruption of F-actin organization. In summary, CRB3 is an actin microfilament regulator, playing a pivotal role in organizing actin filament bundles at the ES.
authors.affiliation: The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, 10065, New York, USA.
authors.forename: Ying
authors.initials: Y
authors.lastname: Gao
authors.affiliation: School of Biological Sciences, University of Hong Kong, Hong Kong, China.
authors.forename: Wing-Yee
authors.initials: WY
authors.lastname: Lui
authors.affiliation: School of Biological Sciences, University of Hong Kong, Hong Kong, China.
authors.forename: Will M
authors.initials: WM
authors.lastname: Lee
authors.affiliation: The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Ave, New York, 10065, New York, USA.
authors.forename: C Yan
authors.initials: CY
authors.lastname: Cheng
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D051378:Actin-Related Protein 3 / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D012708:Sertoli Cells / Q000166:cytology / Q000378:metabolism*; D019108:Tight Junctions / Q000378:metabolism*
chemical_list: D051378:Actin-Related Protein 3; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C498142:Eps8 protein, rat; D008562:Membrane Glycoproteins