Reactive oxygen species modulate independent protein phosphorylation pathways during human sperm capacitation.
Spermatozoa must undergo capacitation to acquire fertilizing ability. Reactive oxygen species (ROS), such as superoxide anion, hydrogen peroxide H2O2, and nitric oxide (NO*), are involved in this process. We investigated the roles and interactions of ROS, the ERK cascade, and the phosphoinositide 3-kinase (PI3K)/Akt axis during human sperm capacitation. Two different agents, fetal cord serum ultrafiltrate and bovine serum albumin, similarly promoted capacitation and the associated phosphorylation of protein tyrosine residues (P-Tyr), threonine-glutamine-tyrosine (P-Thr-Glu-Tyr-P) motif, and MEK-like proteins (P-MEK-like proteins). Components of the ERK pathway modulated these phosphorylation events. ROS increased P-MEK-like proteins and NO* induced P-Thr-Glu-Tyr-P, possibly by acting on or downstream of Ras. The PI3K/Akt axis participated in capacitation and phosphorylation of Tyr and Thr-Glu-Tyr but not MEK-like proteins. H2O2 and NO* induced P-Tyr even in the presence of ERK pathway inhibitors, indicating that ROS also act downstream of this pathway. These new results indicate that ROS act on different transduction elements during sperm capacitation and regulate phosphorylation events that occur in parallel pathways that eventually lead to late phosphorylation of Tyr. These new data reinforce the concept that a complex network of differentially modulated pathways is needed for spermatozoa to become capacitated.
Urology Research Laboratory, Royal Victoria Hospital, and Faculty of Medicine, McGill University, 687 Avenue des Pins Ouest, Montréal, QC, Canada H3A 1A1. coflaher@yahoo.com
Cristián
C
O'Flaherty
Eve
E
de Lamirande
Claude
C
Gagnon
D000730:Androstadienes / Q000494:pharmacology; D001549:Benzamides / Q000494:pharmacology; D002070:Butadienes / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005312:Fetal Blood / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000031:analogs & derivatives / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology; D009570:Nitriles / Q000494:pharmacology; D019319:Okadaic Acid / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D011994:Recombinant Proteins; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013075:Sperm Capacitation / Q000187:drug effects*; D014443:Tyrosine / Q000378:metabolism; D000077191:Wortmannin
D000730:Androstadienes; D001549:Benzamides; D002070:Butadienes; D048049:Extracellular Signal-Regulated MAP Kinases; D006861:Hydrogen Peroxide; D048369:MAP Kinase Kinase 1; D008715:Methionine; D009569:Nitric Oxide; D009570:Nitriles; D019319:Okadaic Acid; D010455:Peptides; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D012710:Serum Albumin, Bovine; D014443:Tyrosine; D000077191:Wortmannin; C120804:CGP 78850; C096856:FTI 277; C121825:N-(5-(3-dimethylaminobenzamido)-2-methylphenyl)-4-hydroxybenzamide; C113580:U 0126