PARENT SESSION

(W414) IDENTIFICATION AND CHARACTERIZATION OF RAFTS IN MEMBRANES OF MOUSE SPERM.

Rodriguez, Delany¹, Lott, William¹, Trevino, Claudia¹, ¹ New Mexico State University, Las Cruces, NM

ABSTRACT- In order to fertilize the egg the sperm should undergo several different processes as activation of hypermotility, Capacitation and Acrosomal Reaction. All these processes involve ion channels of different types. Capacitation is not very well understood but among other things that have being studied there is an increase of the intracellular [Ca²⁺], an increase of the intracellular [pH], a depolarization in the plasma membrane, an increase of intracellular [cAMP], a rearrangement and phosphorylation of the proteins of the plasma membrane. Sperm that do not undergo the capacitation process cannot fertilize an egg. Capacitation can be reproduced in vitro but only30-40% of sperm undergoes the process. It is known that ion channels are localized in different zones of the sperm. Most likely some ion channels can interact with lipidic RAFTS. Lipidic RAFTS are membrane microdomains rich in cholesterol, sphingomyelin, and other phospholipids and glycolipids. RAFTS also have different types of proteins such as Caveolin or Flotillin that help to anchor signaling molecules or ion channels. RAFTS participate in processes of molecular signaling endocytosis, virus and toxin interactions. A variety of ion channels are localized in RAFTS. For the first time we were able to separate capacitated and non capacitated sperm populations by FACS measuring intracellular [Ca²⁺]. We are also trying to identify RAFTS associated molecules (ion channels, signaling molecules and specific phospholipids), by immunoprecipitation and immunocytochemistry.

KEY WORDS: RAFTS, SPERM, CAVELION, CAPACITATION