Spermatogenesis, the sperm-generating process, is a complex process involving mitosis of spermatogonia, meiosis of spermatocytes and spermiogenesis of spermatids. The protein expression levels have been well studied by high-throughput proteomic studies, however, the PTMs including phosphorylation have been less explored. Using advanced mass spectrometry, we successfully identified 17,971 phosphorylation sites of 4131 phosphoproteins from adult mouse testes. Gene ontology annotation reveals that those phosphoproteins mainly function in spermatogenesis, mitosis, transcription, translational regulation and RNA splicing. Substrate and kinase annotation reveals important roles of PLK family kinases in the testicular phosphoproteome. Using small molecule inhibitor of PLKs, we found that PLKs play important functions in the spermatocyte cell line GC2. This mouse testicular phosphoproteome can be a rich resource for the study of mechanisms of spermatogenesis.
In this study, the phosphoproteome in testis was greatly expanded and carefully analyzed. To share the results with the community, the database of pTestis was constructed. All the identified phosphorylation sites in this study were included in the database with detailed annotation from UniProt database. Furthermore, the testis phosphorylation sites from Huttlin et al. were also included. The iGPS prediction results were integrated into the database, which present the potential kinase-substrate regulatory relationships. All the information was available in the pTestis database at http://ptestis.biocuckoo.org/.
For publication of results please cite the following article:
Systematic analysis of the phosphoproteome and kinase-substrate networks in the mouse testis
Lin Qi, Zexian Liu, Wang J., Cui Y., Guo Y., Zhou T., Zhou Z., Yu Xue, Xuejiang Guo, Jiahao Sha.
Mol. Cell. Proteomics, 13(12):3626-38