title: Xepac protein and IP3/Ca2+ pathway implication during Xenopus laevis vitellogenesis.
abstract: The objective of this study was to elucidate the signalling pathways initiated by cAMP once inside the Xenopus laevis oocyte, where it triggers and maintains vitellogenin endocytic uptake. Our results showed the presence of Xepac transcripts at all stages of oogenesis and we demonstrated that a cAMP analogue that exclusively activates Xepac, 8-CPT, was able to rescue the endocytic activity in oocytes with uncoupled gap junctions. Inhibition experiments for the IP3/Ca2+ signalling pathway showed either a complete inhibition or a significant reduction of the vitellogenic process. These results were confirmed with the rescue capability of the A-23187 ionophore in those oocyte batches in which the IP3/Ca2+ pathway was inhibited. Taking our findings into account, we propose that the cAMP molecule binds Xepac protein enabling it to activate the IP3/Ca2+ pathway, which is necessary to start and maintain X. laevis vitellogenin uptake.
authors.affiliation: Instituto Superior de Investigaciones Biológicas (CONICET),Universidad Nacional de Tucumán,Departamento de Biología del Desarrollo,San Miguel de Tucumán,Argentina.
authors.forename: María de los Angeles
authors.initials: Mde L
authors.lastname: Serrano
authors.affiliation: Instituto Superior de Investigaciones Biológicas (CONICET),Universidad Nacional de Tucumán,Departamento de Biología del Desarrollo,San Miguel de Tucumán,Argentina.
authors.forename: Melchor Emilio
authors.initials: ME
authors.lastname: Luque
authors.affiliation: Instituto Superior de Investigaciones Biológicas (CONICET),Universidad Nacional de Tucumán,Departamento de Biología del Desarrollo,Chacabuco 461,T4000ILI San Miguel de Tucumán,Argentina.
authors.forename: Sara Serafina
authors.initials: SS
authors.lastname: Sánchez
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D061207:Calcium Ionophores / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology*; D009866:Oogenesis / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction; D013873:Thionucleotides / Q000494:pharmacology; D014819:Vitellogenins / Q000378:metabolism*; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D061207:Calcium Ionophores; D013873:Thionucleotides; D014819:Vitellogenins; D029867:Xenopus Proteins; D000001:Calcimycin; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D002118:Calcium
keywords: IP3/Ca2+; Vitellogenesis; Xenopus laevis; Xepac; cAMP