The Catsper channel is a sperm-specific, Ca2+-permeable, pH-dependent, and low voltage-dependent channel that is essential for the hyperactivity of sperm flagellum, chemotaxis towards the egg, capacitation and acrosome reaction. All of these physiological events require calcium entry into sperm cells. Remarkably, Catsper genes are exclusively expressed in the testis during spermatogenesis, and ...

The female steroid hormone progesterone regulates ovulation and supports pregnancy, but also controls human sperm function within the female reproductive tract. Progesterone causes elevation of sperm intracellular Ca(2+) leading to sperm hyperactivation, acrosome reaction, and perhaps chemotaxis toward the egg. Although it has been suggested that progesterone-dependent Ca(2+) influx into human ...

The sperm-specific Ca channel CatSper (cation channel of sperm) controls the intracellular Ca concentration and, thereby, the swimming behavior of sperm. Human CatSper is activated by progesterone (1, 2), an oviductal hormone, which stimulates Ca influx and motility responses. By patch-clamp recording from human sperm, Mannowetz et al. (3) studied the action of the steroids pregnenolone sulfate...

The four sperm-specific CatSper ion channel proteins are required for hyperactivated motility and male fertility, and for Ca(2+) entry evoked by alkaline depolarization. In the absence of external Ca(2+), Na(+) carries current through CatSper channels in voltage-clamped sperm. Here we show that CatSper channel activity can be monitored optically with the [Na(+)](i)-reporting probe SBFI in popul...

The cation channel of sperm (CatSper) comprises four transmembrane subunits specifically expressed in human, equine, murine and ovine spermatozoa, apparently implicated in capacitation, hyperactivation and acrosome exocytosis. Western blotting and immunocytochemistry showed hereby that CatSper subunits are also present in boar spermatozoa, primarily over the sperm neck, tail and cytoplasmic dro...

CatSper channel has been considered the principal sperm Ca2+ channel responsible for the cytosolic Ca2+ elevation required for various sperm functions necessary for fertilization [1-4]. However, the mechanism underlying the activation of CatSper channel by various physiological ligands remain incompletely understood. We have recently demonstrated the expression of C-C chemokine receptor 6 (CCR6...

Sperm guidance is controlled by chemical and physical cues. In many species, Ca(2+) bursts in the flagellum govern navigation to the egg. In Arbacia punctulata, a model system of sperm chemotaxis, a cGMP signaling pathway controls these Ca(2+) bursts. The underlying Ca(2+) channel and its mechanisms of activation are unknown. Here, we identify CatSper Ca(2+) channels in the flagellum of A. punc...

A recent study in Science finds that α/β-hydrolase domain-containing protein 2 (ABHD2) is a novel nongenomic progesterone receptor that holds the CatSper cation channel open while progesterone elevates sperm cytoplasmic calcium ion (Ca) levels and triggers sperm hyperactive motility. ABHD2 functions as a lipid hydrolase, breaking down arachidonoylglycerols (2-AG/1AG)—endocannabinoid components ...

The calcium channel of sperm (CatSper) is essential for sperm hyperactivated motility and fertility. The steroid hormone progesterone activates CatSper of human sperm via binding to the serine hydrolase ABHD2. However, steroid specificity of ABHD2 has not been evaluated. Here, we explored whether steroid hormones to which human spermatozoa are exposed in the male and female genital tract influe...

The basal fungus Allomyces macrogynus (A. macrogynus) produces motile male gametes displaying well-studied chemotaxis toward their female counterparts. This chemotaxis is driven by sirenin, a sexual pheromone released by the female gametes. The pheromone evokes a large calcium influx in the motile gametes, which could proceed through the cation channel of sperm (CatSper) complex. Herein, we rep...