Identification and differential expression of two non-testis specific CABYR variants, bind to GSK3□ with a proline-rich extensin-like domain and act as a substrate

• Main Authors: Yun-Lin Li, 李泳鈴
• Other Authors: Yi-Ren Hong
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/50622428530421742782

碩士 === 高雄醫學大學 === 醫學研究所碩士班 === 92 === 英文摘要 Glycogen synthase kinase-3□ (GSK3□), a conserved multifunctional kinase, play roles in regulating glycogen metabolism, gene expression, cell proliferation and survival. To examine other possible roles for GSK3□ function using human GSK3□ as a bait in the yeast two-hybrid system. We showed that CABYR was identified as GSK3□ binding protein. A CABYR variant (CABYR-493) has been reported as a testis-specific calcium binding tyrosine phosphorylation regulated fibrous sheath protein involved in capacitation. In this study, our data indicated that two variants of CABYR (-281 and -379), but not CABYR-493, interacted with GSK3□ in the yeast two-hybrid method and GST pull-down assay. Molecular characterization showed that CABYR-281 and —379 variants bind to GSK3□ with middle region and formed a dimer using C-terminal region with extensin domain. However, cellular localization experiment showed that all three CABYR variants nearly localize in nucleus. Interestingly, RT-PCR combining southern blot showed that CABYR-281 and —379 were not only restricted to express in testis. In addition, the data also showed that CABYR-281 and -379 variants were differential expressed in various brain tumors and several cancer cell lines examined, suggesting that CABYR-281 and -379 may exhibit aberrant expression in brain tumors and cancer cell lines. Furthermore, our data also found that GSK3□ is able to phosphorylate CABYR variants, suggesting that phosphorylation may play a role for more CABYR functions in different tissues other than sperm capacitation.