title: Abnormalities in focal adhesion complex formation, regulation, and function in human autosomal recessive polycystic kidney disease epithelial cells.
abstract: Integrin-associated focal adhesion complex formation and turnover plays an essential role in directing interactions between epithelial cells and the extracellular matrix during organogenesis, leading to appropriate cell spreading, cell-matrix adhesion, and migration. Autosomal recessive polycystic kidney disease (ARPKD) is associated with loss of function of PKHD1-encoded protein fibrocystin-1 and is characterized by cystic dilation of renal collecting tubules (CT) in utero and loss of renal function in patients if they survive the perinatal period. Normal polycystin-1 (PC-1)/focal adhesion complex function is required for control of CT diameter during renal development, and abnormalities in these complexes have been demonstrated in human PC-1 mutant cystic cells. To determine whether loss of fibrocystin-1 was associated with focal adhesion abnormalities, ARPKD cells or normal age-matched human fetal (HF)CT cells in which fibrocystin-1 had been decreased by 85% by small interfering RNA inhibition were compared with normal HFCT. Accelerated attachment and spreading on collagen matrix and decreased motility of fibrocystin-1-deficient cells were associated with longer paxillin-containing focal adhesions, more complex actin-cytoskeletal rearrangements, and increased levels of total beta(1)-integrin, c-Src, and paxillin. Immunoblot analysis of adhesive cells using site-specific phospho-antibodies demonstrated ARPKD-associated loss of activation of focal adhesion kinase (FAK) by phosphorylation at its autophosphorylation site (Y397); accelerated FAK inhibition by phosphorylation at Y407, S843, and S910; as well as increased activation of c-Src at pY418. Paxillin coimmunoprecipitation analyses suggested that fibrocystin-1 was a component of the normal focal adhesion complex and that actin and fibrocystin-1 were lost from ARPKD complexes.
authors.affiliation: Department of Medicine, Division of Nephrology, Mount Sinai School of Medicine, New York, New York, USA.
authors.forename: Sharon
authors.initials: S
authors.lastname: Israeli
authors.forename: Kurt
authors.initials: K
authors.lastname: Amsler
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Zheleznova
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Wilson
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D022001:Focal Adhesions / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D051419:Paxillin / Q000235:genetics / Q000378:metabolism; D017044:Polycystic Kidney, Autosomal Recessive / Q000235:genetics / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D050396:TRPP Cation Channels / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D051416:Focal Adhesion Protein-Tyrosine Kinases; D051419:Paxillin; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D050396:TRPP Cation Channels; C451750:PKHD1 protein, human