title: BMP type I receptor complexes have distinct activities mediating cell fate and axon guidance decisions.
abstract: The finding that morphogens, signalling molecules that specify cell identity, also act as axon guidance molecules has raised the possibility that the mechanisms that establish neural cell fate are also used to assemble neuronal circuits. It remains unresolved, however, how cells differentially transduce the cell fate specification and guidance activities of morphogens. To address this question, we have examined the mechanism by which the Bone morphogenetic proteins (BMPs) guide commissural axons in the developing spinal cord. In contrast to studies that have suggested that morphogens direct axon guidance decisions using non-canonical signal transduction factors, our results indicate that canonical components of the BMP signalling pathway, the type I BMP receptors (BMPRs), are both necessary and sufficient to specify the fate of commissural neurons and guide their axonal projections. However, whereas the induction of cell fate is a shared property of both type I BMPRs, axon guidance is chiefly mediated by only one of the type I BMPRs, BMPRIB. Taken together, these results indicate that the diverse activities of BMP morphogens can be accounted for by the differential use of distinct components of the canonical BMPR complex.
authors.affiliation: Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Ken
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Keith D
authors.initials: KD
authors.lastname: Phan
authors.forename: Samantha J
authors.initials: SJ
authors.lastname: Butler
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D002642:Chick Embryo; D005260:Female; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D008959:Models, Neurological; D046912:Multiprotein Complexes; D011247:Pregnancy; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013116:Spinal Cord / Q000196:embryology / Q000378:metabolism
chemical_list: D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins; D052005:Bone Morphogenetic Protein Receptors, Type I