title: Rab3d is required for Xenopus anterior neurulation by regulating Noggin secretion.
abstract: Rab3d is a member of the Ras-related small GTPase family of secretory Rab, Rab3. In this study, we showed that Xenopus Rab3d is expressed specifically in the anterior border of the neural plate when the neural plate converges and folds to initiate neural tube formation. Morpholino-mediated knockdown of Rab3d resulted in neurulation defects both in neural plate convergence and folding. Interestingly, perturbation of BMP signaling rescued neurulation defects of Rab3d morphants, suggesting that Rab3d inhibits BMP signaling during neurulation. By secretion assay in the Xenopus animal cap, we found that Rab3d specifically regulates secretion of a BMP antagonist, Noggin, but not Chordin and Wnts. We also found that Rab3d is co-localized with Noggin and that this interaction is dependent on the GTP/GDP cycle of Rab3d. Collectively, these findings suggest that Rab3d-mediated secretion regulation of a BMP antagonist, Noggin, is one of the mechanisms of BMP antagonism during Xenopus anterior neurulation.
authors.affiliation: Division of Molecular and Life Sciences, Pohang University of Science and Technology, Kyungbuk, Republic of Korea.
authors.forename: Hyunjoon
authors.initials: H
authors.lastname: Kim
authors.forename: Jin-Kwan
authors.initials: JK
authors.lastname: Han
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019485:Bone Morphogenetic Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology; D002118:Calcium / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D054261:Neurulation / Q000235:genetics* / Q000502:physiology; D011485:Protein Binding; D055571:Secretory Pathway / Q000187:drug effects / Q000235:genetics; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D020692:rab3 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000099176:Noggin Protein
chemical_list: D019485:Bone Morphogenetic Proteins; D002118:Calcium; D002352:Carrier Proteins; D029867:Xenopus Proteins; D020692:rab3 GTP-Binding Proteins; D000099176:Noggin Protein; C561475:Rab3d protein, Xenopus