molecular mechanism for human sperm chemotaxis mediated by progesterone孕激素对人类精子趋化作用的分子机制.pdfVIP

Molecular Mechanism for Human Sperm Chemotaxis Mediated by Progesterone 1 1 ˜ 1 2 3 Maria E. Teves , Hector A. Guidobaldi , Diego R. Unates , Raul Sanchez , Werner Miska , Stephen J. 4 ´ 4 1 Publicover , Aduen A. Morales Garcia , Laura C. Giojalas * ´ ´ ´ ´ ´ 1 Centro de Biologıa Celular y Molecular, Universidad Nacional de Cordoba, Cordoba, Argentina, 2 Centro de Biotecnologıa de la Reproduccion, Departamento de Ciencias ´ Preclınicas, Universidad de La Frontera, Temuco, Chile, 3 Centre for Dermatology and Andrology, Justus Liebig University, Giessen, Germany, 4 School of Biosciences, University of Birmingham, Birmingham, United Kingdom Abstract Sperm chemotaxis is a chemical guiding mechanism that may orient spermatozoa to the egg surface. A picomolar concentration gradient of Progesterone (P), the main steroidal component secreted by the cumulus cells that surround the egg, attracts human spermatozoa. In order to elucidate the molecular mechanism of sperm chemotaxis mediated by P, we combine the application of different strategies: pharmacological inhibition of signaling molecules, measurements of the concentrations of second messengers and activation of the chemotactic signaling. Our data implicate a number of classic signal transduction pathways in the response and provide a model for the sequence of events, where the tmAC-cAMP-PKA pathway is activated first, followed by protein tyrosine phosphorylation (equatorial band and flagellum) and calcium mobilization (through