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Updated: Jun 11, 2026
Phosphopeptide Analysis of Rodent Epididymal Spermatozoa
Published on: December 30, 2014
New candidate targets of protein phosphatase-1c-gamma-2 in mouse testis revealed by a differential phosphoproteome
H Henderson1, G Macleod, C Hrabchak
1Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada.
Abstract:
Reversible phosphorylation has been implicated in many developmental processes. Dephosphorylation is mediated by several families of phosphatases, including type 1 serine/threonine phosphatases (protein phosphatase-1 or PP1). The loss of the murine Ppp1cc gene causes male infertility as a result of impaired spermatogenesis. Ppp1cc encodes two splice isoforms, PPP1CC1 and PPP1CC2, with the latter being the most abundant isoform in the testis. However, the details of PPP1CC2's involvement in spermatogenesis are still unknown. As a phosphatase has been removed from the mutant mouse, a search for hyperphosphorylated proteins in the mutant testis may reveal the direct downstream targets of PPP1CC2. Using a whole tissue proteomics approach to identify testis-specific dephosphorylation targets of PPP1CC2, we found that two-dimensional electrophoresis identified 10 potential targets in the Ppp1cc null testis several of which are factors known to be important for spermatogenesis, such as HSPA2. Another potential target, tubulin, was found to be misregulated during Ppp1cc(-/-) spermatogenesis, disrupting manchette development. This work represents the first survey of the testicular phosphoproteome under pathological conditions.
Insights
Protein phosphatase-1 (PP1) is crucial for male fertility. Loss of the Ppp1cc gene impairs spermatogenesis by affecting protein dephosphorylation, leading to male infertility and disrupted manchette development in mice.
Area of Science:
- Molecular Biology
- Reproductive Biology
- Proteomics
Background:
- Reversible phosphorylation regulates key developmental processes.
- Protein phosphatase-1 (PP1) is a major serine/threonine phosphatase family.
- Loss of murine Ppp1cc gene leads to male infertility due to impaired spermatogenesis.
Purpose of the Study:
- To identify testis-specific dephosphorylation targets of PPP1CC2.
- To understand the role of PPP1CC2 in spermatogenesis.
Main Methods:
- Whole tissue proteomics approach.
- Two-dimensional electrophoresis (2-DE) on Ppp1cc null testis.
- Identification of hyperphosphorylated proteins.
Main Results:
- Identified 10 potential dephosphorylation targets of PPP1CC2 in Ppp1cc null testis.
- HSPA2, a known spermatogenesis factor, was identified as a potential target.
- Tubulin was found to be misregulated, disrupting manchette development.
Conclusions:
- This study provides the first survey of the testicular phosphoproteome under pathological conditions.
- PPP1CC2 plays a critical role in spermatogenesis, potentially through the regulation of targets like HSPA2 and tubulin.
- Disruption of PPP1CC2 function leads to male infertility and defects in sperm development.
