Transcriptomic and proteomic identification of signaling molecules involved in egg activation in the sea star, Patiria miniata
Bates, Lauren Shea
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During egg activation in all species, the critical mechanism to restart the zygote metabolism and prevent polyspermy is an intracellular Ca2+ increase. The signaling molecules, including the receptors on the sperm and egg, leading to the Ca2+ rise are not fully known. In the sea star, Patiria miniata, SFK1, SFK3, and PLCγ are known signaling molecules who are responsible for causing the internal Ca2+ rise from the endoplasmic reticulum. These three proteins share common features including signaling through SH2 domains and their activity is controlled by tyrosine phosphorylation. Using transcriptomics and phospho-proteomics to search for more molecules with these same features in P. miniata mature and fertilized eggs, I identified more potential signaling molecules involved in the egg activation pathway. The most promising candidate signaling molecule being a Vav2 protein, which has both an SH2 domain and is phosphorylated upon fertilization, as identified in both the P. miniata mature egg transcriptome and in fertilized egg samples from tyrosine phosphorylation immunoprecipitations. The findings in this dissertation provide several databases for future researchers to select candidate molecules to test their function in egg activation. The more knowledge gained of the molecular components of the egg activation pathway will lead to novel contraception methods and infertility testing and treatments.