Proteomic and phosphoproteomic profiling during diapause entrance in the flesh fly, Sarcophaga crassipalpis.

Diapause is an alternate developmental pathway that is regulated by the neuroendocrine system in insects. To date, much of the information that has been published regarding the possible molecular events associated with diapause have been at the level of transcription. However, since transcription and translation are not linked in eukaryotic systems, a proteomics approach may represent a better tool to identify the gene products that regulate this period of developmental arrest. In this study, we performed gel-based proteomic and phospho-proteomic analyses to identify proteins that are differentially expressed or differentially phosphorylated in the brain during the initiation of pupal diapause in the flesh fly, Sarcophaga crassipalpis. A total of 27 proteins and phosphoproteins were identified by LC-MS/MS, including 16 that were either upregulated or phosphorylated during diapause, including proteins that function in cellular defense, cell cycle inhibition and neuronal protection. Of equal importance, 11 proteins were identified that were either downregulated at the total protein level, or from nuclear fractions. These included proteins involved in cell proliferation, adult development and aging. These data provide potentially valuable insight into the regulation of insect dormancy as well as the general phenomenon of aging in eukaryotic systems.