Activity of calcineurin governs the phosphorylated state of PKC substrates involved in Amphibian sperm motility.

O'BRIEN ED; KRAPF D; CABADA MO; VISCONTI PE; ARRANZ SE

Plymouth, NH

Conferencia; gordon research conference; fertilization and activation of development; 2011

The cAMP-dependent protein kinase (PKA) governs relevant functions in sperm, including motility, in almost every species studied. In animals with external fertilization as amphibians, spermatozoa are stored in a quiescent state in the testis. Hypotonic fertilization media triggers activation of sperm motility. In our previous work, we found that a pathway involving transmembrane adenylyl cyclase/cAMP/PKA regulates Bufo arenarum sperm motility. Interestingly, activation of PKA correlates with a decrease of phosphorylated state of PKC substrates. However, pharmacological inhibition of PKC impairs progressive sperm motility. The lowering of phospho-PKC-substrates is drastically influenced by activation of a calcium-dependent ser/thr phosphatase (PP2B or calcinuerin), rather that by a decrease of PKC activity itself. These results contribute to elucidate the molecular mechanisms underlying the regulation of Amphibian sperm motility triggered by osmotic shock, suggesting the existence of tight regulation between PKA and PKC activities.