Abstract
Rai14 (retinoic acid induced protein 14) is an actin binding protein first identified in the liver, highly expressed in the placenta, the testis, and the eye. In the course of studying actin binding proteins that regulate the organization of actin filament bundles in the ectoplasmic specialization (ES), a testis-specific actin-rich adherens junction (AJ) type, Rai14 was shown to be one of the regulatory proteins at the ES. In the rat testis, Rai14 was found to be expressed by Sertoli and germ cells, structurally associated with actin and an actin cross-linking protein palladin. Its expression was the highest at the ES in the seminiferous epithelium of adult rat testes, most notably at the apical ES at the Sertoli-spermatid interface, and expressed stage-specifically during the epithelial cycle in stage VII-VIII tubules. However, Rai14 was also found at the basal ES near the basement membrane, associated with the blood-testis barrier (BTB) in stage VIII-IX tubules. A knockdown of Rai14 in Sertoli cells cultured in vitro by RNAi was found to perturb the Sertoli cell tight junction-permeability function in vitro, mediated by a disruption of F-actin, which in turn led to protein mis-localization at the Sertoli cell BTB. When Rai14 in the testis in vivo was knockdown by RNAi, defects in spermatid polarity and adhesion, as well as spermatid transport were noted mediated via changes in F-actin organization and mis-localization of proteins at the apical ES. In short, Rai14 is involved in the re-organization of actin filaments in Sertoli cells during the epithelial cycle, participating in conferring spermatid polarity and cell adhesion in the testis.
Highlights
IntroductionAnkycorbin (ankyrin repeat- and coiled-coil structure-containing protein) was first purified from rat liver as a 125 kDa actinbinding protein, and cloned using a mouse cDNA library in 2000 [1]
Ankycorbin was first purified from rat liver as a 125 kDa actinbinding protein, and cloned using a mouse cDNA library in 2000 [1]
We focused on the apical ectoplasmic specialization (ES) because studies on the stage-specific and spatiotemporal expression of Rai14 in the seminiferous epithelium indicated that its localization at the apical ES displayed more subtle changes during the epithelial cycle
Summary
Ankycorbin (ankyrin repeat- and coiled-coil structure-containing protein) was first purified from rat liver as a 125 kDa actinbinding protein, and cloned using a mouse cDNA library in 2000 [1]. It contained 6 ankyrin repeats near its N-terminus with two coil-coil domains near its C-terminus and was called ankycorbin [1]. Since Rai appears to be a more widely used name in the field including several vendors that produced this antibody, we elected to use Rai in this report While this protein was shown to be an actin-associated protein more than a decade ago, its function in the testis remains largely unknown
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
