One direction of our research is to understand the mechanisms by which the sperm motility and male fertility are regulated by ion channels. In particular, we are studying the sperm-specific calcium channels “CatSper” that are essential for sperm hyperactivation. To identify molecules underlying mammalian sperm hyperactivation, we take comparative genomic and proteomic approach to find candidate genes in the CatSper-mediated Ca2+ signaling pathway.

We are functionally characterizing sperm cells from the mice deficient in candidate genes from the screens. We test fertility by natural mating and IVF, sperm motility in vitro for hyperactivation and sperm rheotaxis, and in vivo for sperm migration. Sperm motility is correlated with functionl and molecular changes by employing high-speed, high-resolution video microscopy for dynamic optical imaging of fluorescently labeled live cells and super-resolution imaging for molecular distribution in fine details.

Photo credit: Jean-Ju Chung