Modification of the composition of polycystin-1 multiprotein complexes by calcium and tyrosine phosphorylation.
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.
Mesh Terms:
Cadherins, Calcium, Cell Adhesion, Cell Adhesion Molecules, Cells, Cultured, Centrifugation, Density Gradient, Collagen, Cytochalasin D, Cytoskeletal Proteins, Epithelial Cells, Extracellular Matrix, Focal Adhesion Kinase 1, Focal Adhesion Protein-Tyrosine Kinases, Focal Adhesions, Humans, Immunoblotting, Immunohistochemistry, Kidney Tubules, Collecting, Phosphorylation, Polycystic Kidney, Autosomal Dominant, Precipitin Tests, Protein-Tyrosine Kinases, Proteins, TRPP Cation Channels, Time Factors, Trans-Activators, Tyrosine, Tyrphostins, beta Catenin
Cadherins, Calcium, Cell Adhesion, Cell Adhesion Molecules, Cells, Cultured, Centrifugation, Density Gradient, Collagen, Cytochalasin D, Cytoskeletal Proteins, Epithelial Cells, Extracellular Matrix, Focal Adhesion Kinase 1, Focal Adhesion Protein-Tyrosine Kinases, Focal Adhesions, Humans, Immunoblotting, Immunohistochemistry, Kidney Tubules, Collecting, Phosphorylation, Polycystic Kidney, Autosomal Dominant, Precipitin Tests, Protein-Tyrosine Kinases, Proteins, TRPP Cation Channels, Time Factors, Trans-Activators, Tyrosine, Tyrphostins, beta Catenin
Biochim. Biophys. Acta
Date: Dec. 15, 2000
PubMed ID: 11113628
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