In all mammalian species studied so far, sperm capacitation correlates with an increase in protein tyrosine (Tyr) phosphorylation mediated by a bicarbonate-dependent cAMP/protein kinase A (PKA) pathway. Recent studies in mice revealed, however, that a Src family kinase (SFK)-induced inactivation of serine/threonine (Ser/Thr) phosphatases is also involved in the signaling pathways leading to Tyr...

After ejaculation, the mammalian male gamete must undergo the capacitation process, which is a prerequisite for egg fertilization. The bioenergetics of sperm capacitation is poorly understood despite its fundamental role in sustaining the biochemical and molecular events occurring during gamete activation. Glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) are the two major metabol...

The aim of the present investigation was to compare Tyrode’s albumin lactate pyruvate (TALP) medium and TRIS citrate medium for capacitation of caprine sperm. In experiment 1 capacitation was assessed by chlortetracycline assay and in experiment 2 with in vitro fertilization and embryo development. In experiment 2, cumulus oocyte complexes (COCs) recovered by slicing the caprine ovaries were ma...

Abstract Study question Are S-sulfenylation and S-nitrosylation, two essential posttranslational modifications (PTMs), increased during sperm capacitation? Which proteins are subjected to S-sulfenylation? Summary answer S-nitrosylation increase capacitation. affects certain proteins, including A-kinase anchor protein 13, Fibrilline-1, Spermatogenesis-associated 7. What is known already There a ...

STUDY QUESTION Does fibronectin (Fn) stimulate the sperm capacitation process in humans? SUMMARY ANSWER Fibronectin stimulates human sperm capacitation. WHAT IS KNOWN ALREADY Capacitation is a process that occurs in the oviduct. It has been suggested that some molecules present in the oviductal fluid and cells as well as proteins present in the cumulus oophorus could be involved in the modu...

Unlike most cells of the body which function in an ionic environment controlled within narrow limits, spermatozoa must function in a less controlled external environment. In order to better understand how sperm control their membrane potential in different ionic conditions, we measured mouse sperm membrane potentials under a variety of conditions and at different external K(+) concentrations, b...

Density gradient centrifugation of semen is commonly used in many assisted reproduction techniques. Although gradients have the potential to isolate and enrich motile and viable spermatozoa, the centrifugation force presents a stress factor to cell organelles and membranes. The objective of the study was to evaluate the impact of density gradient centrifugation stress on sperm capacitation dyna...

The aim of this study was to evaluate the effects of Ca, HCO3 and BSA on the in vitro capacitation-associated protein tyrosine phosphorylation, hyperactivation and acrosome reaction in guinea pig sperm. Caudal epididymal sperm were incubated in four different groups: modified TALP (Tyrode’s albumin lactate pyruvate) or TALP without one of the medium constituents (Ca, HCO3 and BSA). After incuba...

Protein phosphorylation is involved in sperm capacitation, so the effect of protein phosphatase inhibitors on the capacitation of spermatozoa of males with unexplained infertility was investigated. d-mannose ligand specific receptor expression in fresh, living spermatozoa, capacitated or treated with calyculin A (an inhibitor of protein phosphatases 1 and 2A), was studied in three groups of men...

BACKGROUND Serum albumin is a key component in mammalian sperm capacitation, a functional maturation process by which sperm become competent to fertilize oocytes. Capacitation is accompanied by several cellular and molecular changes including an increased tyrosine phosphorylation of sperm proteins and a development of hyperactivated sperm motility. Both of these processes require extracellular ...