β1 integrin NPXY motifs regulate kidney collecting-duct development and maintenance by induced-fit interactions with cytosolic proteins

Mol Cell Biol. 2012 Oct;32(20):4080-91. doi: 10.1128/MCB.00568-12. Epub 2012 Aug 6.

Abstract

Loss of β1 integrin expression inhibits renal collecting-system development. Two highly conserved NPXY motifs in the distal β1 tail regulate integrin function by associating with phosphtyrosine binding (PTB) proteins, such as talin and kindlin. Here, we define the roles of these two tyrosines in collecting-system development and delineate the structural determinants of the distal β1 tail using nuclear magnetic resonance (NMR). Mice carrying alanine mutations have moderate renal collecting-system developmental abnormalities relative to β1-null mice. Phenylalanine mutations did not affect renal collecting-system development but increased susceptibility to renal injury. NMR spectra in bicelles showed the distal β1 tail is disordered and does not interact with the model membrane surface. Alanine or phenylalanine mutations did not alter β1 structure or interactions between α and β1 subunit transmembrane/cytoplasmic domains; however, they did decrease talin and kindlin binding. Thus, these studies highlight the fact that the functional roles of the NPXY motifs are organ dependent. Moreover, the β1 cytoplasmic tail, in the context of the adjacent transmembrane domain in bicelles, is significantly different from the more ordered, membrane-associated β3 integrin tail. Finally, tyrosine mutations of β1 NPXY motifs induce phenotypes by disrupting their interactions with critical integrin binding proteins like talins and kindlins.

Publication types

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

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Cytosol / metabolism
  • Humans
  • Integrin beta1 / genetics
  • Integrin beta1 / metabolism*
  • Integrin beta3 / chemistry
  • Integrin beta3 / metabolism
  • Kidney Tubules, Collecting / growth & development*
  • Membrane Proteins / chemistry
  • Mice
  • Molecular Sequence Data
  • Mutation
  • Neoplasm Proteins / chemistry
  • Protein Binding
  • Protein Conformation
  • Talin / chemistry
  • Tyrosine / chemistry
  • Tyrosine / genetics
  • Tyrosine / metabolism

Substances

  • FERMT1 protein, human
  • Integrin beta1
  • Integrin beta3
  • Membrane Proteins
  • Neoplasm Proteins
  • Talin
  • Tyrosine