CONICET | Buscador de Institutos y Recursos Humanos

Caltrin (calcium transport inhibitor) is a family of small and basic proteins of the mammalian seminal plasma which bind to spermcells during ejaculation and inhibit the extracellular Ca2+ uptake, preventing the premature acrosomal exocytosis and hyperactivation whensperm cells ascend through the female reproductive tract. The binding of caltrin proteins to specific areas of the sperm surface suggests theexistence of caltrin receptors, or precise protein-phospholipid arrangements in the sperm membrane, distributed in the regions where Ca2+influx may take place. However, the molecular mechanisms of recognition and interaction between caltrin and spermatozoa have not beenelucidated. Therefore, the aim of this article is to describe in depth the known structural features and functional properties of caltrin proteins, tofind out how they may possibly interact with the sperm membranes to control the intracellular signaling that trigger physiological events requiredfor fertilization.