CABYR binds to AKAP3 and Ropporin in the human sperm fibrous sheath

作     者：Yan-Feng Li Wei He Arabinda Mandal Young-Hwan Kim Laura Digilio Ken Klotz Charles J Flickinger John C Herr 

作者机构：Department of Urology Daping Hospital Institute of Surgery Research Third Military Medical University Chongqing 400042 China Department of Obstetrics and GynecologySouthwest Hospital Third Military Medical University Chongqing 400038 China Center for Research in Contraceptive and Reproductive Health Department of Cell BiologyUniversity of Virginia Charlottesville VA 22908 USA 

出 版 物：《Asian Journal of Andrology》 (亚洲男性学杂志（英文版）)

年 卷 期：2011年第13卷第2期

页      面：266-274页

核心收录：

学科分类：0821[工学-纺织科学与工程] 1002[医学-临床医学] 0905[农学-畜牧学] 08[工学] 09[农学] 090501[农学-动物遗传育种与繁殖] 082101[工学-纺织工程] 

基　　金：Fogarty International Center  NIH  USA 

主　　题：AKAP3 CABYR fibrous sheath Ropporin sperm tail spermatozoa Western blotting 

摘      要：Calcium-binding tyrosine phosphorylation-regulated protein （CABYR） is a highly polymorphic calcium-binding tyrosine- and serine-/threonine-phosphorylated fibrous sheath （FS） protein involved in capacitation. A putative domain （amino acids 12-48） homologous to the regulatory subunit of type II cAMP-dependent protein kinase A （RII） dimerisation and A kinase-anchoring protein （AKAP）-binding domains of protein kinase A at the N-terminus suggests that CABYR may self-assemble and bind to AKAPs. Moreover, there is evidence that CABYR has limited interaction with AKAPs. However, further evidence and new relationships between CABYR and other FS proteins, including AKAPs, will be helpful in understanding the basic physiology of FS. In this study, a new strategy for co-immunoprecipitation of insoluble proteins, as well as the standard co-immunoprecipitation method in combination with mass spectrometry and western blot, was employed to explore the relationship between CABYR, AKAP3 and Ropperin. The results showed that AKAP3 was *** with CABYR by the anti-CABYR-A polyclonal antibody, and, conversely, CABYR was also *** with AKAP3 by the anti-AKAP3 polyclonal antibody. Another RIl-like domain containing protein, Ropporin, was also co-immunoprecipitated with CABYR, indicating that Ropporin is one of CABYR＇s binding partners. The interactions between CABYR, AKAP3 and Ropporin were confirmed by yeast two-hybrid assays. Further analysis showed that CABYR not only binds to AKAP3 by its RII domain but binds to Ropporin through other regions besides the RIl-like domain. This is the first demonstration that CABYR variants form a complex not only with the scaffolding protein AKAP3 but also with another Rll-like domain-containing protein in the human sperm FS.