Ana M. Salicioni
Research Assistant Professor of Veterinary and Animal Science, University of Massachusetts
Ph.D.: University of San Luis, Argentina Postdoctoral Training: St George's Hospital Medical School, London, UK; Fox Chase Cancer Center, PA
Our research is focused on understanding the cell signaling events conducive to sperm capacitation as well as the mechanism(s) by which the capacitated sperm is then able to induce activation and to trigger development in mammalian eggs, ultimately leading to a successful development of the embryo. As part of this task, we are interested in identifying the molecule(s) involved in these events in male germ cells, among which we count the novel family of testis-specific serine protein kinases (TSSKs). The TSSK protein family belongs to the AMPK kinase branch in the CAMK group, and is composed of six members, TSSK1 through TSSK6; whether Tssk5 has all the domains required to be an active kinase has not yet been determined. Using an array of TSSK specific antibodies, we have investigated the localization of TSSKs in mouse and human sperm and demonstrated that TSSK1, TSSK2, TSSK4 and TSSK6 are present in mature sperm (Li et al., 2011). Our studies have provided further support to previous observations indicating that TSSK family members display a different cellular localization, thus suggesting a non-redundant role for these protein kinases. The restricted expression of TSSKs during differentiation of spermatids in the testis, as well as the importance of phosphorylation in signaling pathways, has lead to the prediction that TSSK(s) have an important role(s) in germ cell differentiation and/or sperm function. This prediction has been recently confirmed by the sterile phenotype of the Tssk6 knock-out mice (Spiridonov et al., 2005, Sosnik et al., 2009)and of the double Tssk1 and Tssk2 KO (Xu et al., 2008; Shang et al., 2010). Despite these new discoveries, the specific function and mode of action of Tssks in male reproduction has yet to be determined.