Vijayaraghavan Srinivasan, Chakrabarti Rumela, Myers Kimberley
Department of Biological Sciences, Kent State University, Kent, Ohio, USA.
Soc Reprod Fertil Suppl. 2007;63:111-21.
The intracellular mediators cyclic AMP, calcium and pH regulate sperm function through changes in protein phosphorylation. Protein phosphorylation is the net result of the actions of protein kinases and phosphatases. The protein phosphatase isoform, PPlgamma2, with a unique C-terminus extension is highly enriched in spermatozoa and testis. Changes in PPlgamma2 catalytic activity, its phosphorylation, and binding to its regulatory proteins change during epididymal maturation. Thus PPgamma2 is a key protein in sperm motility regulation; decreased enzyme activity is associated with increased motility. This review summarizes the current knowledge of this sperm protein phosphatase. The biochemical properties of its regulatory proteins, sds22 and protein 14-3-3, among others, are discussed. Future studies will elucidate sperm signalling pathways involving PP1gamma2 and determine if the unique structure of PP1gamma2 is critical to normal male gamete development and function. Understanding the role of PP1gamma2 will not only contribute to the basic understanding of male gamete functions but also has practical applications in clinical andrology and in the development of male contraceptives.
细胞内介质环磷酸腺苷（cAMP）、钙和pH通过蛋白质磷酸化的变化来调节精子功能。蛋白质磷酸化是蛋白激酶和磷酸酶作用的最终结果。具有独特C末端延伸的蛋白磷酸酶同工型PPlgamma2在精子和睾丸中高度富集。在附睾成熟过程中，PPlgamma2的催化活性、磷酸化及其与调节蛋白的结合会发生变化。因此，PPgamma2是精子运动调节中的关键蛋白；酶活性降低与运动性增加有关。本综述总结了目前对这种精子蛋白磷酸酶的认识。讨论了其调节蛋白sds22和14-3-3蛋白等的生化特性。未来的研究将阐明涉及PP1gamma2的精子信号通路，并确定PP1gamma2的独特结构是否对正常雄配子的发育和功能至关重要。了解PP1gamma2的作用不仅有助于对雄配子功能的基本理解，而且在临床男科学和男性避孕药开发中具有实际应用价值。
