TY - JOUR
T1 - CatSper channels are regulated by protein kinase A
AU - Orta, Gerardo
AU - De La Vega-Beltran, José Luis
AU - Martín-Hidalgo, X. David
AU - Santi, Celia M.
AU - Visconti, Pablo E.
AU - Darszon, X. Alberto
N1 - Funding Information:
This study was supported by Eunice Kennedy Shriver NICHD, National Insti-tutes of Health Grant RO1 HD38082 (to P. E. V), by Consejo Nacional de Ciencia y Tecnología Grants Fronteras 71 39908-Q and CB 2015/255914 from Mexico (CONACyT) (to A. D.), and by Dirección General de Asuntos del Personal Académico of the Universidad Nacional Autónoma de México (DGAPA-UNAM) Grants IN205516 (to A. D.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2018 American Society for Biochemistry and Molecular Biology Inc. All rights reserved.
PY - 2019/10/26
Y1 - 2019/10/26
N2 - Mammalian sperm must undergo capacitation as a preparation for entering into hyperactivated motility, undergoing the acrosome reaction, and acquiring fertilizing ability. One of the initial capacitation events occurs when sperm encounter an elevated HCO3- concentration. This anion activates the atypical adenylyl cyclase Adcy10, increases intracellular cAMP, and stimulates protein kinase A (PKA). Moreover, an increase in intracellular Ca2+ concentration ([Ca2+]i) is essential for sperm capacitation. Although a cross-talk between cAMP-dependent pathways and Ca2+ clearly plays an essential role in sperm capacitation, the connection between these signaling events is incompletely understood. Here, using three different approaches, we found that CatSper, the main sperm Ca2+ channel characterized to date, is up-regulated by a cAMP-dependent activation of PKA in mouse sperm. First, HCO3- and the PKA-activating permeable compound 8-Br-cAMP induced an increase in [Ca2+]i, which was blocked by the PKA peptide inhibitor PKI, and H89, another PKA inhibitor, also abrogated the 8-Br-cAMP response. Second, HCO3- increased the membrane depolarization induced upon divalent cation removal by promoting influx of monovalent cations through CatSper channels, which was inhibited by PKI, H89, and the CatSper blocker HC-056456. Third, electrophysiological patch clamp, wholecell recordings revealed that CatSper activity is up-regulated by HCO3- and by direct cAMP injection through the patch-clamp pipette. The activation by HCO3- and cAMP was also blocked by PKI, H89, Rp-cAMPS, and HC-056456, and electrophysiological recordings in sperm from CatSper-KO mice confirmed CatSper's role in these activation modes. Our results strongly suggest that PKA-dependent phosphorylation regulates [Ca2+]i homeostasis by activating CatSper channel complexes.
AB - Mammalian sperm must undergo capacitation as a preparation for entering into hyperactivated motility, undergoing the acrosome reaction, and acquiring fertilizing ability. One of the initial capacitation events occurs when sperm encounter an elevated HCO3- concentration. This anion activates the atypical adenylyl cyclase Adcy10, increases intracellular cAMP, and stimulates protein kinase A (PKA). Moreover, an increase in intracellular Ca2+ concentration ([Ca2+]i) is essential for sperm capacitation. Although a cross-talk between cAMP-dependent pathways and Ca2+ clearly plays an essential role in sperm capacitation, the connection between these signaling events is incompletely understood. Here, using three different approaches, we found that CatSper, the main sperm Ca2+ channel characterized to date, is up-regulated by a cAMP-dependent activation of PKA in mouse sperm. First, HCO3- and the PKA-activating permeable compound 8-Br-cAMP induced an increase in [Ca2+]i, which was blocked by the PKA peptide inhibitor PKI, and H89, another PKA inhibitor, also abrogated the 8-Br-cAMP response. Second, HCO3- increased the membrane depolarization induced upon divalent cation removal by promoting influx of monovalent cations through CatSper channels, which was inhibited by PKI, H89, and the CatSper blocker HC-056456. Third, electrophysiological patch clamp, wholecell recordings revealed that CatSper activity is up-regulated by HCO3- and by direct cAMP injection through the patch-clamp pipette. The activation by HCO3- and cAMP was also blocked by PKI, H89, Rp-cAMPS, and HC-056456, and electrophysiological recordings in sperm from CatSper-KO mice confirmed CatSper's role in these activation modes. Our results strongly suggest that PKA-dependent phosphorylation regulates [Ca2+]i homeostasis by activating CatSper channel complexes.
UR - http://www.scopus.com/inward/record.url?scp=85055614252&partnerID=8YFLogxK
U2 - 10.1074/jbc.RA117.001566
DO - 10.1074/jbc.RA117.001566
M3 - Article
C2 - 30213858
AN - SCOPUS:85055614252
SN - 0021-9258
VL - 293
SP - 16830
EP - 16841
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 43
ER -