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Sperm motility characteristics are regulated by changes in carboxy methylation and tyrosine phosphorylation of protein phosphatase PP2A
Author(s) -
Dudiki Tejasvi,
Kadunganattil Suraj,
Ramdas Shandilya,
Vijayaraghavan Srinivasan
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.766.10
Subject(s) - protein phosphatase 2 , sperm motility , sperm , phosphatase , phosphorylation , motility , tyrosine phosphorylation , biology , epididymis , protein tyrosine phosphatase , chemistry , microbiology and biotechnology , genetics
The enzymes PP2A and PP1γ2 are the two major serine/threonine phosphatases in mammalian spermatozoa. PP2A is implicated in diverse cellular functions. In this study, we confirm the presence of PP2A in spermatozoa by western blot and show that it is carboxy methylated (Lys 309) and reciprocally tyrosine phosphorylated (Tyr 307). Mammalian spermatozoa acquire motility and their ability to fertilize eggs during their transit through the epididymis. PP2A of immotile sperm from late caput region of the epididymis is methylated with negligible tyrosine phosphorylation whereas PP2A from motile sperm of cauda epididymis is demethylated and tyrosine phosphorylated. Protein phosphatase assay shows that demethylation lowers catalytic activity of PP2A in motile caudal sperm compared to immotile caput sperm. Demethylation of PP2A occurred in the presence of nanomolar levels of okadaic acid or with increased intrasperm S‐adenosyl homocysteine levels. Increased PP2A demethylation converts caudal sperm motility into patterns resembling hyperactivation. These treatments however have no effect on immotile caput sperm. The enzymes PME‐1 and PPMT1 responsible for demethylation and methylation of PP2A respectively, along with SAH hydrolase are present in sperm. Thus PP2A regulated by methylation plays a role in modulating sperm motility characteristics essential for fertilization. (NIH‐HD38520)