title: Modification of the composition of polycystin-1 multiprotein complexes by calcium and tyrosine phosphorylation.
abstract: Mutations in the PKD1 gene are responsible for >85% of autosomal dominant polycystic kidney disease (ADPKD). The protein product of PKD1, polycystin-1, is a large, modular membrane protein, with putative ligand-binding motifs in the extracelluar N-terminal portion, 9-11 transmembrane domains and an intracellular C-terminal portion with phosphorylation sites. A role for polycystin-1 as a cell surface receptor involved in cell-matrix and cell-cell interactions has been proposed. In this study, we have analyzed polycystin-1 and associated protein distribution in normal human epithelial cells and examined the role of cell-matrix versus cell-cell interactions in regulation of the assembly of polycystin-1 multiprotein complexes. Immunocytochemistry, sucrose density gradient sedimentation, co-immunoprecipitation analyses and in vitro binding assays have shown that polycystin-1 associates with the focal adhesion proteins talin, vinculin, p130Cas, FAK, alpha-actinin, paxillin and pp60c-src in subconfluent normal human fetal collecting tubule (HFCT) epithelia when cell-matrix interactions predominate. Polycystin-1 also forms higher S value complexes with the cell-cell adherens junction proteins E-cadherin, beta- and gamma-catenins in confluent cultures when cell-cell interactions are predominant. Polycystin-1 multiprotein complexes can be disrupted by cytochalasin D but not by colchicine, suggesting involvement of the actin cytoskeleton. Although inhibition of tyrosine phosphorylation by tyrphostin inhibits polycystin-1-FAK interactions, E-cadherin interactions are enhanced. High calcium treatment also increases polycystin-1-E-cadherin interactions.
authors: Division of Nephrology, Department of Medicine, Mount Sinai School of Medicine, Box 1243, 1 Gustave L. Levy Place, 10029, New York, NY 10029, USA.
authors: L
authors: L
authors: Geng
authors: C R
authors: CR
authors: Burrow
authors: H P
authors: HP
authors: Li
authors: P D
authors: PD
authors: Wilson
mesh_terms: D015820:Cadherins / Q000737:chemistry; D002118:Calcium / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000737:chemistry*; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D003094:Collagen; D015638:Cytochalasin D / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000737:chemistry; D004847:Epithelial Cells / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D022001:Focal Adhesions / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007685:Kidney Tubules, Collecting / Q000737:chemistry / Q000196:embryology* / Q000378:metabolism*; D010766:Phosphorylation; D016891:Polycystic Kidney, Autosomal Dominant / Q000235:genetics; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000737:chemistry; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D050396:TRPP Cation Channels; D013997:Time Factors; D015534:Trans-Activators; D014443:Tyrosine / Q000737:chemistry; D020032:Tyrphostins / Q000494:pharmacology; D051176:beta Catenin
chemical_list: D015820:Cadherins; D002118:Calcium; D015815:Cell Adhesion Molecules; D003094:Collagen; D015638:Cytochalasin D; D003598:Cytoskeletal Proteins; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D011505:Protein-Tyrosine Kinases; D011506:Proteins; D050396:TRPP Cation Channels; D015534:Trans-Activators; D014443:Tyrosine; D020032:Tyrphostins; D051176:beta Catenin; C495270:CTNNB1 protein, human; C496050:PTK2 protein, human