Crystal structure of kindlin-2 PH domain reveals a conformational transition for its membrane anchoring and regulation of integrin activation

Protein Cell. 2012 Jun;3(6):434-40. doi: 10.1007/s13238-012-2046-1. Epub 2012 May 31.

Abstract

Kindlin-2 belongs to a subfamily of FERM domain containing proteins, which plays key roles in activating integrin transmembrane receptors and mediating cell adhesion. Compared to conventional FERM domains, kindlin-2 FERM contains an inserted pleckstrin homology (PH) domain that specifically binds to phosphatidylinositol (3,4,5) trisphosphate (PIP3) and regulates the kindlin-2 function. We have determined the crystal structure of kindlin-2 PH domain at 1.9 Å resolution, which reveals a conserved PH domain fold with a highly charged and open binding pocket for PIP3 head group. Structural comparison with a previously reported solution structure of kindlin-2 PH domain bound to PIP3 head group reveals that upon PIP3 insertion, there is a significant conformational change of both the highly positively charged loop at the entry of the PIP3 binding pocket and the entire β barrel of the PH domain. We propose that such "induced-fit" type change is crucial for the tight binding of PIP3 to anchor kindlin-2 onto the membrane surface, thereby promoting its binding to integrins. Our results provide important structural insight into kindlin-2-mediated membrane anchoring and integrin activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Crystallography, X-Ray
  • Cytoskeletal Proteins / chemistry*
  • Cytoskeletal Proteins / metabolism*
  • Humans
  • Integrins / metabolism*
  • Membrane Proteins / chemistry*
  • Membrane Proteins / metabolism*
  • Mice
  • Models, Molecular
  • Muscle Proteins / chemistry*
  • Muscle Proteins / metabolism*
  • Neoplasm Proteins / chemistry*
  • Neoplasm Proteins / metabolism*
  • Protein Conformation

Substances

  • Cytoskeletal Proteins
  • FERMT3 protein, human
  • Integrins
  • Membrane Proteins
  • Muscle Proteins
  • Neoplasm Proteins
  • kindlin-2 protein, mouse

Associated data

  • PDB/4F7H