Modulation of embryonic intracellular Ca2+ signaling by Wnt-5A.
Wnt genes encode secreted proteins which are implicated in receptor-mediated cell-cell signaling events important in embryogenesis, but the second messenger systems modulated by Wnts have not been identified. We report that ectopic expression of Xwnt-5A in zebrafish embryos enhances the frequency of intracellular Ca2+ transients in the enveloping layer of the blastodisc, whereas Xwnt-8 does not. These transients are independent of extracellular Ca2+. Consistent with the observed Ca2+ transients playing a role in responses of embryos to Xwnt-5A, we report that the ligand-activated serotonin type 1C receptor, which stimulates PI cycle activity and Ca2+ signaling independent of Wnts, phenocopies embryonic responses to Xwnt-5A. These results suggest that intercellular signaling by a subset of vertebrate Wnts involves modulation of a intracellular Ca2+ signaling pathway, which may arise from phosphatidylinositol cycle activity.
Slusarski
D C
DC
Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle 98195, USA.
Yang-Snyder
J
J
Busa
W B
WB
Moon
R T
RT
D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000502:physiology*; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin / Q000096:biosynthesis / Q000502:physiology*; D015398:Signal Transduction; D014714:Vertebrates; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D015027:Zebrafish
D011518:Proto-Oncogene Proteins; D044405:Receptor, Serotonin, 5-HT2C; D011985:Receptors, Serotonin; C085389:WNT5A protein, human; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; D002118:Calcium