title: 18 wheeler regulates apical constriction of salivary gland cells via the Rho-GTPase-signaling pathway.
abstract: Rho GTPase and its upstream activator, guanine nucleotide exchange factor 2 (RhoGEF2), have emerged as key regulators of actin rearrangements during epithelial folding and invagination (Nikolaidou, K.K., Barrett, K. (2004). A Rho-GTPase-signaling pathway is used reiteratively in epithelial folding and potentially selects the outcome of Rho activation. Curr. Biol. 14, 1822-1826). Here, we show that Drosophila 18 wheeler (18W), a Toll-like receptor protein, is a novel component of the Rho-signaling pathway involved in epithelial morphogenesis. 18w Mutant embryos have salivary gland invagination defects similar to embryos that lack components of the Rho pathway, and ubiquitous expression of 18W results in an upregulation of Rho signaling. Transheterozygous genetic interactions and double mutant analysis suggest that 18W affects the Rho-GTPase-signaling pathway not through Fog and RhoGEF2, but rather by inhibiting Rho GTPase activating proteins (RhoGAPs). We show that RhoGAP5A and RhoGAP88C/Crossveinless-c (CV-C) are required for proper salivary gland morphogenesis, implicating them as potential targets of 18W.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
authors.forename: Tereza
authors.initials: T
authors.lastname: Kolesnikov
authors.forename: Steven K
authors.initials: SK
authors.lastname: Beckendorf
mesh_terms: D000818:Animals; D015815:Cell Adhesion Molecules / Q000172:deficiency / Q000502:physiology*; D003251:Constriction, Pathologic / Q000235:genetics; D004330:Drosophila; D029721:Drosophila Proteins / Q000172:deficiency / Q000502:physiology*; D004625:Embryo, Nonmammalian; D004848:Epithelium / Q000254:growth & development; D020690:GTPase-Activating Proteins / Q000037:antagonists & inhibitors; D008565:Membrane Proteins / Q000172:deficiency / Q000502:physiology*; D009024:Morphogenesis; D009154:Mutation / Q000502:physiology; D012469:Salivary Glands / Q000473:pathology*; D015398:Signal Transduction; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
chemical_list: C094464:18w protein, Drosophila; D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins; D020690:GTPase-Activating Proteins; D008565:Membrane Proteins; D020741:rho GTP-Binding Proteins