Functional differences between kindlin-1 and kindlin-2 in keratinocytes

J Cell Sci. 2012 May 1;125(Pt 9):2172-84. doi: 10.1242/jcs.096214. Epub 2012 Feb 10.

Abstract

Integrin-β1-null keratinocytes can adhere to fibronectin through integrin αvβ6, but form large peripheral focal adhesions and exhibit defective cell spreading. Here we report that, in addition to the reduced avidity of αvβ6 integrin binding to fibronectin, the inability of integrin β6 to efficiently bind and recruit kindlin-2 to focal adhesions directly contributes to these phenotypes. Kindlins regulate integrins through direct interactions with the integrin-β cytoplasmic tail and keratinocytes express kindlin-1 and kindlin-2. Notably, although both kindlins localize to focal adhesions in wild-type cells, only kindlin-1 localizes to the integrin-β6-rich adhesions of integrin-β1-null cells. Rescue of these cells with wild-type and chimeric integrin constructs revealed a correlation between kindlin-2 recruitment and cell spreading. Furthermore, despite the presence of kindlin-1, knockdown of kindlin-2 in wild-type keratinocytes impaired cell spreading. Our data reveal unexpected functional consequences of differences in the association of two homologous kindlin isoforms with two closely related integrins, and suggest that despite their similarities, different kindlins are likely to have unique functions.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Antigens, Neoplasm / metabolism*
  • Cell Adhesion / physiology
  • Fibronectins / metabolism
  • Flow Cytometry
  • Focal Adhesions
  • Gene Knockout Techniques
  • Humans
  • Integrin beta1 / genetics
  • Integrin beta1 / metabolism*
  • Integrins / metabolism*
  • Keratinocytes / cytology
  • Keratinocytes / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / metabolism*
  • Sequence Alignment

Substances

  • Antigens, Neoplasm
  • FERMT1 protein, human
  • FERMT3 protein, human
  • Fibronectins
  • Integrin beta1
  • Integrins
  • Membrane Proteins
  • Neoplasm Proteins
  • integrin alphavbeta6