Proteins implicated in sperm capacitation.

Spermatozoa after being deposited in the female reproductive tract spend a considerable time in this foreign environment prior to fertilization of the oocyte. Chang and Austin independently observed1,2 that this time spent by the spermatozoa in the female tract is not consequential but a necessary event in the life cycle of the male gamete, and Austin2 first called this maturation period of spermatozoa as 'Capacitation'. Ever since, attempts have been made to understand and unravel the molecular mechanism of capacitation. Based on the results obtained so far, it is clear that capacitation is guided by novel signal transduction pathways influencing varied aspects of spermatozoa. Capacitation could be, thus, defined as the cumulative molecular, cellular and physiological changes that occur in spermatozoa in the female reproductive tract to achieve the final competence to fertilize the oocyte. This review is structured so as to first understand the key features of capacitation and then to survey the players which bring about these changes during capacitation.