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Role for PP1γ2 in spermatogenesis and sperm morphogenesis

Chakrabarti, Rumela
http://rave.ohiolink.edu/etdc/view?acc_num=kent1176430377

Abstract Details

2007, PHD, Kent State University, College of Biomedical Sciences.
Protein Ser/Thr phosphatase-1 (PP1) is a ubiquitous enzyme that controls numerous cellular processes by affecting phosphorylation of key regulatory proteins. The major isoformsof PP1 are α, β, γ1, and γ2, the latter two being derived through alternate splicing of asingle gene. All four isoforms are about 98% identical except at their C-termini. These PP1 isoforms have distinct tissue and subcellular distribution, however their exact role is still unclear. The PP1γ2 splice variant is the most abundant PP1 isoform expressed in the testis. We have also shown that PP1γ2 is a key signaling enzyme regulating protein phosphorylation in spermatozoa. Targeted disruption of the Ppp1cc gene causes male infertility in mice due to impaired spermiogenesis. This study was undertaken to determine the expression patterns of specific PP1 isoforms in testis of wild-type mice and to establish how the defects produced in Ppp1cc-null developing sperm are related to loss of PP1γ isoform expression. We observed that PP1γ2 was prominently expressed in cytoplasm of secondary spermatocytes and round spermatids as well as in elongating spermatids and testicular and epididymal spermatozoa, while its expression was weak or absent in spermatogonia, pachytene spermatocytes, and interstitial cells. In contrast, a high-level of PP1γ1 expression was observed in interstitial cells, while much weaker expression was observed in all stages of spermatogenesis. Another PP1 isoform, PP1α was predominant in spermatogonia, pachytene spermatocytes, and interstitial cells. Examining the temporal expression of PP1 enzymes in testes, revealed a striking postnatal increase in PP1γ2 levels compared to other isoforms. Testicular sperm tails from Ppp1cc-null mice showed malformed mitochondrial sheaths, extra outer dense fibers and fibrous sheath in both the middle and principal pieces. These data suggest that, in addition to its previously documented role in motility, PP1γ2 is involved in sperm tail morphogenesis.
Srinivasan Vijayaraghavan (Advisor)
137 p.
sperm; testes; spermatogenesis; protein phosphatase; knock out; spermatid

Recommended Citations

Citations

  • Chakrabarti, R. (2007). Role for PP1γ2 in spermatogenesis and sperm morphogenesis [Doctoral dissertation, Kent State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=kent1176430377

    APA Style (7th edition)

  • Chakrabarti, Rumela. Role for PP1γ2 in spermatogenesis and sperm morphogenesis. 2007. Kent State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=kent1176430377.

    MLA Style (8th edition)

  • Chakrabarti, Rumela. "Role for PP1γ2 in spermatogenesis and sperm morphogenesis." Doctoral dissertation, Kent State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=kent1176430377

    Chicago Manual of Style (17th edition)

kent1176430377
548
© 2007, all rights reserved.
This open access ETD is published by Kent State University and OhioLINK.