title: SEC14 and spectrin domains 1 (Sestd1) and Dapper antagonist of catenin 1 (Dact1) scaffold proteins cooperatively regulate the Van Gogh-like 2 (Vangl2) four-pass transmembrane protein and planar cell polarity (PCP) pathway during embryonic development in mice.
abstract: The planar cell polarity (PCP) pathway is a conserved non-canonical (β-catenin-independent) branch of Wnt signaling crucial to embryogenesis, during which it regulates cell polarity and polarized cell movements. Disruption of PCP components in mice, including Vangl2 and Dact1, results in defective neural tube closure and other developmental defects. Here, we show that Sestd1 is a novel binding partner of Vangl2 and Dact1. The Sestd1-Dact1 interface is formed by circumscribed regions of Sestd1 (the carboxyl-terminal region) and Dact1 (the amino-terminal region). Remarkably, we show that loss of Sestd1 precisely phenocopies loss of Dact1 during embryogenesis in mice, leading to a spectrum of birth malformations, including neural tube defects, a shortened and/or curly tail, no genital tubercle, blind-ended colons, hydronephrotic kidneys, and no bladder. Moreover, as with Dact1, a knock-out mutation at the Sestd1 locus exhibits reciprocal genetic rescue interactions during development with a semidominant mutation at the Vangl2 locus. Consistent with this, examination of Wnt pathway activities in Sestd1 mutant mouse embryonic tissue reveals disrupted PCP pathway biochemistry similar to that characterized in Dact1 mutant embryos. The Sestd1 protein is a divergent member of the Trio family of GTPase regulatory proteins that lacks a guanine nucleotide exchange factor domain. Nonetheless, in cell-based assays the Sestd1-Dact1 interaction can induce Rho GTPase activation. Together, our data indicate that Sestd1 cooperates with Dact1 in Vangl2 regulation and in the PCP pathway during mammalian embryonic development.
authors.affiliation: Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, University of California, San Francisco, California 94158-2324, USA.
authors.forename: XiaoYong
authors.initials: X
authors.lastname: Yang
authors.forename: Benjamin N R
authors.initials: BN
authors.lastname: Cheyette
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D016764:Cell Polarity; D002478:Cells, Cultured; D004622:Embryo, Mammalian / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D047108:Embryonic Development; D004789:Enzyme Activation; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D016601:RNA-Binding Proteins; D015398:Signal Transduction / Q000235:genetics; D060449:Wnt Signaling Pathway / Q000235:genetics; D020741:rho GTP-Binding Proteins / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C431577:Ltap protein, mouse; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C583618:Sestd1 protein, mouse; C508545:frodo protein, mouse; D020741:rho GTP-Binding Proteins
keywords: Cell Migration; Cell Polarity; Mouse Genetics; Planar Cell Polarity (PCP) Pathway; Rho; Transgenic Mice; Wnt Signaling