Epidermal growth factor receptor pathway substrate 8 (Eps8) is a novel regulator of cell adhesion and the blood-testis barrier integrity in the seminiferous epithelium.
In the seminiferous epithelium, Eps8 is localized to actin-based cell junctions at the blood-testis barrier (BTB) and the apical ectoplasmic specialization (ES) in stage V-VI tubules but is considerably diminished in stage VIII tubules. Eps8 down-regulation coincides with the time of BTB restructuring and apical ES disassembly, implicating the role of Eps8 in cell adhesion. Its involvement in Sertoli-germ cell adhesion was substantiated in studies using an in vivo animal model by treating rats with 1-(2,4-dichlorobenzy)-1H-indazole-3-carbohydrazide (adjudin) to induce anchoring junction restructuring, during which Eps8 disappeared at the apical ES before germ cell departure. In Sertoli cell cultures with established permeability barrier mimicking the BTB in vivo, the knockdown of Eps8 by RNAi led to F-actin disorganization and the mislocalization of the tight junction proteins occludin and ZO-1, suggesting the function of Eps8 in maintaining BTB integrity. In vivo knockdown of Eps8 in the testis caused germ cell sloughing and BTB damage, concomitant with occludin mislocalization, further validating that Eps8 is a novel regulator of cell adhesion and BTB integrity in the seminiferous epithelium.
Lie
Pearl P Y
PP
Center for Biomedical Research, Population Council, 1230 York Ave., New York, NY 10065, USA.
Mruk
Dolores D
DD
Lee
Will M
WM
Cheng
C Yan
CY
D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing; D022005:Adherens Junctions / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001814:Blood-Testis Barrier / Q000187:drug effects / Q000502:physiology*; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D006834:Hydrazines / Q000494:pharmacology; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D011506:Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D034622:RNA Interference; D051381:Rats; D017207:Rats, Sprague-Dawley; D012670:Seminiferous Epithelium / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D012708:Sertoli Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D013087:Spermatids / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D013091:Spermatogenesis / Q000502:physiology
C432482:1-(2,4-dichlorobenzyl)indazole-3-carbohydrazide; D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; C498142:Eps8 protein, rat; D006834:Hydrazines; D007191:Indazoles; D011506:Proteins