Formation and phosphorylation of the PINCH-1-integrin linked kinase-alpha-parvin complex are important for regulation of renal glomerular podocyte adhesion, architecture, and survival

J Am Soc Nephrol. 2005 Jul;16(7):1966-76. doi: 10.1681/ASN.2004121112. Epub 2005 May 4.

Abstract

Alterations in the cellular architecture, adhesion, and/or loss of glomerular podocytes are causal factors in the development of proteinuria and the progression to end-stage renal failure. With the use of an inducible podocyte differentiation system, it was found that the cellular levels of PINCH-1, integrin linked kinase (ILK), and alpha-parvin, cytoplasmic components of cell-extracellular matrix adhesions, were significantly increased during podocyte differentiation. Concomitantly, an increased amount of the PINCH-1-ILK-alpha-parvin complex was detected in the differentiated, foot process-containing podocytes. Overexpression of the PINCH-1-binding ankyrin repeat domain of ILK but not that of a PINCH-1-binding defective mutant form of the ankyrin domain effectively inhibited the formation of the PINCH-1-ILK-alpha-parvin complex. Disruption of the PINCH-1-ILK-alpha-parvin complex significantly reduced the podocyte-matrix adhesion and foot process formation. Furthermore, a marked increase of apoptosis in the podocytes in which the assembly of the PINCH-1-ILK-alpha-parvin complex was compromised was detected. Inhibition of ILK with a small compound inhibitor also altered podocyte cytoskeleton and increased apoptosis. Finally, it is shown that alpha-parvin is phosphorylated in podocytes. Mutations at the alpha-parvin N-terminal proline-directed serine phosphorylation sites reduced its complex formation with ILK and resulted in defects in podocyte adhesion, architecture, and survival. These results provide important evidence for a crucial role of the PINCH-1-ILK-alpha-parvin complex in the control of podocyte adhesion, morphology, and survival.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actinin / genetics
  • Actinin / metabolism*
  • Adaptor Proteins, Signal Transducing
  • Animals
  • Apoptosis / physiology
  • Cell Adhesion / physiology
  • Cell Differentiation
  • Cell Survival / physiology
  • Cells, Cultured
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Epithelial Cells / physiology*
  • Extracellular Matrix / physiology
  • Kidney Glomerulus / cytology
  • Kidney Glomerulus / physiology*
  • LIM Domain Proteins
  • Membrane Proteins
  • Mice
  • Microfilament Proteins
  • Phosphorylation
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • DNA-Binding Proteins
  • LIM Domain Proteins
  • Lims1 protein, mouse
  • Membrane Proteins
  • Microfilament Proteins
  • PARVA protein, human
  • Actinin
  • integrin-linked kinase
  • Protein Serine-Threonine Kinases