title: The exocyst protein Sec10 interacts with Polycystin-2 and knockdown causes PKD-phenotypes.
abstract: Autosomal dominant polycystic kidney disease (ADPKD) is characterized by formation of renal cysts that destroy the kidney. Mutations in PKD1 and PKD2, encoding polycystins-1 and -2, cause ADPKD. Polycystins are thought to function in primary cilia, but it is not well understood how these and other proteins are targeted to cilia. Here, we provide the first genetic and biochemical link between polycystins and the exocyst, a highly-conserved eight-protein membrane trafficking complex. We show that knockdown of exocyst component Sec10 yields cellular phenotypes associated with ADPKD, including loss of flow-generated calcium increases, hyperproliferation, and abnormal activation of MAPK. Sec10 knockdown in zebrafish phenocopies many aspects of polycystin-2 knockdown-including curly tail up, left-right patterning defects, glomerular expansion, and MAPK activation-suggesting that the exocyst is required for pkd2 function in vivo. We observe a synergistic genetic interaction between zebrafish sec10 and pkd2 for many of these cilia-related phenotypes. Importantly, we demonstrate a biochemical interaction between Sec10 and the ciliary proteins polycystin-2, IFT88, and IFT20 and co-localization of the exocyst and polycystin-2 at the primary cilium. Our work supports a model in which the exocyst is required for the ciliary localization of polycystin-2, thus allowing for polycystin-2 function in cellular processes.
authors.affiliation: Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Ben
authors.initials: B
authors.lastname: Fogelgren
authors.forename: Shin-Yi
authors.initials: SY
authors.lastname: Lin
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zuo
authors.forename: Kimberly M
authors.initials: KM
authors.lastname: Jaffe
authors.forename: Kwon Moo
authors.initials: KM
authors.lastname: Park
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Reichert
authors.forename: P Darwin
authors.initials: PD
authors.lastname: Bell
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Burdine
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Lipschutz
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D002923:Cilia / Q000235:genetics / Q000378:metabolism; D004285:Dogs; D004789:Enzyme Activation / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000196:embryology / Q000473:pathology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D008954:Models, Biological; D010641:Phenotype; D007690:Polycystic Kidney Diseases / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D011485:Protein Binding; D050396:TRPP Cation Channels / Q000172:deficiency / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D020929:Mitogen-Activated Protein Kinase Kinases; D050396:TRPP Cation Channels; D025521:Tumor Suppressor Proteins; D033921:Vesicular Transport Proteins; D029961:Zebrafish Proteins; C419575:EXOC5 protein, human; C487991:IFT20 protein, human; C098623:IFT88 protein, human; C560185:exoc5 protein, zebrafish