title: A Point Mutation in p190A RhoGAP Affects Ciliogenesis and Leads to Glomerulocystic Kidney Defects.
abstract: Rho family GTPases act as molecular switches regulating actin cytoskeleton dynamics. Attenuation of their signaling capacity is provided by GTPase-activating proteins (GAPs), including p190A, that promote the intrinsic GTPase activity of Rho proteins. In the current study we have performed a small-scale ENU mutagenesis screen and identified a novel loss of function allele of the p190A gene Arhgap35, which introduces a Leu1396 to Gln substitution in the GAP domain. This results in decreased GAP activity for the prototypical Rho-family members, RhoA and Rac1, likely due to disrupted ordering of the Rho binding surface. Consequently, Arhgap35-deficient animals exhibit hypoplastic and glomerulocystic kidneys. Investigation into the cystic phenotype shows that p190A is required for appropriate primary cilium formation in renal nephrons. P190A specifically localizes to the base of the cilia to permit axoneme elongation, which requires a functional GAP domain. Pharmacological manipulations further reveal that inhibition of either Rho kinase (ROCK) or F-actin polymerization is able to rescue the ciliogenesis defects observed upon loss of p190A activity. We propose a model in which p190A acts as a modulator of Rho GTPases in a localized area around the cilia to permit the dynamic actin rearrangement required for cilia elongation. Together, our results establish an unexpected link between Rho GTPase regulation, ciliogenesis and glomerulocystic kidney disease.
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Katherine
authors: K
authors: Stewart
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Yaned
authors: Y
authors: Gaitan
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Maxwell E R
authors: ME
authors: Shafer
authors: Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada.
authors: Lamine
authors: L
authors: Aoudjit
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Di
authors: D
authors: Hu
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Richa
authors: R
authors: Sharma
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Mathieu
authors: M
authors: Tremblay
authors: Department of Anatomy and Cell Biology, McGill University, and Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
authors: Hidetaka
authors: H
authors: Ishii
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Michael
authors: M
authors: Marcotte
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Daniela
authors: D
authors: Stanga
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: You Chi
authors: YC
authors: Tang
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Sami Kamel
authors: SK
authors: Boualia
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Alana H T
authors: AH
authors: Nguyen
authors: Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada.
authors: Tomoko
authors: T
authors: Takano
authors: Department of Anatomy and Cell Biology, McGill University, and Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
authors: Nathalie
authors: N
authors: Lamarche-Vane
authors: Department of Human Genetics and Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada.
authors: Silvia
authors: S
authors: Vidal
authors: Goodman Cancer Research Centre and Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
authors: Maxime
authors: M
authors: Bouchard
mesh_terms: D000199:Actins / Q000378:metabolism; D000483:Alleles; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D002923:Cilia / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology; D005038:Ethylnitrosourea; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D020690:GTPase-Activating Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D052177:Kidney Diseases, Cystic / Q000235:genetics* / Q000473:pathology; D007678:Kidney Glomerulus / Q000378:metabolism / Q000473:pathology*; D007684:Kidney Tubules / Q000002:abnormalities / Q000473:pathology; D008297:Male; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009436:Neural Tube Defects / Q000473:pathology; D038081:Organogenesis; D010641:Phenotype; D017354:Point Mutation / Q000235:genetics*; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D000199:Actins; C513041:Arhgap35 protein, mouse; D020690:GTPase-Activating Proteins; D012097:Repressor Proteins; D005038:Ethylnitrosourea