REGULATION OF PP1γ2 IN TESTIS/SPERMATOZOA BYPPP1R11/PPP1R7/PPP1R2

In mouse testis, PP1γ1 is restricted mainly to somatic cells, while PP1γ2 is primarily located in secondary spermatocytes and germ cells, and the only isoform detectable in mammalian spermatozoa. Targeted deletion of the PP1γ gene results in sterile male mice. Because the most prominent marker of this phenotype is aberrant spermatid morphogenesis, its primary cause may be the absence of PP1γ2 since PP1γ1 is mainly in somatic cells. To better understand the role of PP1γ2 in mammalian testis/sperm, this dissertation was undertaken to explore PP1γ2 interactions with its regulatory proteins in testis/sperm. Wild-type and mutant isoforms of PPP1R11/inhibitor 3 (I3), PPP1R2/inhibitor 2 (I2) and a novel protein similar to I2 were studied. The studies from this dissertation provide important insights into the regulation of PP1γ2 in testis and sperm.