| Title | Evidence for the involvement of proline-directed serine/threonine phosphorylation in sperm capacitation. |
| Publication Type | Journal Article |
| Year of Publication | 2006 |
| Authors | Jha KN, Salicioni AM, Arcelay E, Chertihin O, Kumari S, Herr JC, Visconti PE |
| Journal | Molecular human reproduction |
| Volume | 12 |
| Issue | 12 |
| Pagination | 781-9 |
| Date Published | 2006 Dec |
| ISSN | 1360-9947 |
| Keywords | 1-Methyl-3-isobutylxanthine, Amino Acid Motifs, Animals, Antibodies, Monoclonal, beta-Cyclodextrins, Blotting, Western, Bucladesine, Butadienes, Cattle, Cholesterol, Cyclic AMP, Flavonoids, Humans, Male, Mice, Mitogen-Activated Protein Kinase 1, Mitogen-Activated Protein Kinase 3, Mitosis, Nitriles, Phosphoproteins, Phosphorylation, Proline, Protein Processing, Post-Translational, Protein-Serine-Threonine Kinases, Serum Albumin, Bovine, Sodium Bicarbonate, Sperm Capacitation, Spermatozoa |
| Abstract | To become fertilization competent, mammalian sperm undergo changes in the female reproductive tract termed capacitation. Capacitation correlates with an increase in tyrosine phosphorylation; however, less is known about the role of serine/threonine phosphorylation in this process. Proline-directed phosphorylation is one of the major regulatory phosphorylation events in many cellular processes such as cell proliferation and differentiation. Using mitotic phosphoprotein monoclonal-2 (MPM-2) antibody in this study, we observed that several mouse sperm proteins in the range of 70-250 kDa underwent increased serine/threonine-proline phosphorylation during capacitation. In contrast to the time course of tyrosine phosphorylation, proline-directed phosphorylation could be observed at shorter time points of sperm incubation, and it was found to be independent of NaHCO(3) and adenosine 3’5’-cyclic monophosphate (cAMP). Similar to the regulation of the increase in tyrosine phosphorylation, cholesterol acceptors such as bovine serum albumin (BSA) or 2-hydroxypropyl-beta-cyclodextrin (2-OH-propyl-beta-CD) were essential for the regulation of proline-directed phosphorylation in mouse sperm. Furthermore, it was also found to be BSA dependent in human sperm. Among proline-directed kinases, extracellular signal-regulated kinase 1/2 (ERK1/2) is present in mammalian sperm; nevertheless, U0126 and PD098059, two inhibitors of the ERK pathway, did not block this phosphorylation in mouse sperm. In conclusion, capacitation is associated with an increase in proline-directed phosphorylation linked to cholesterol efflux in the sperm. |
| DOI | 10.1093/molehr/gal085 |
| Alternate Journal | Mol. Hum. Reprod. |
| PubMed ID | 17050774 |
