The hinge region of the scaffolding protein of cell contacts, zonula occludens protein 1, regulates interacting with various signaling proteins

J Cell Biochem. 2012 Mar;113(3):934-45. doi: 10.1002/jcb.23422.

Abstract

Zonula occludens protein 1 (ZO-1) is a ubiquitous scaffolding protein, but it is unknown why it functions in very different cellular contacts. We hypothesized that a specific segment, the unique hinge region, can be bound by very different regulatory proteins. Using surface plasmon resonance spectroscopy and binding assays to peptide libraries, we show, for the first time, that the hinge region directly interacts with disparate signal elements such as G-proteins alpha 12 and alpha i2, the regulator of G-protein signaling 5, multifunctional signaling protein ahnak1, and L-type Ca2+-channel beta-2-subunit. The novel binding proteins specifically bound to a coiled coil-helix predicted in the hinge region of ZO-. The interactions were modulated by phosphorylation in the hinge helix. Activation of the G-proteins influenced their association to ZO-1. In colon cells, G alpha i2 and ZO-1 were associated, as shown by coimmunoprecipitation. After cotransfection in kidney cells, G alpha i2 barely colocalized with ZO-1; the colocalization coefficient was significantly increased when epinephrine activated G-protein signaling. In conclusion, proteins with different regulatory potential adhere to and influence cellular functions of ZO-proteins, and the interactions can be modulated via its hinge region and/or the binding proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Caco-2 Cells
  • Cell Membrane / chemistry
  • Epithelial Cells / chemistry
  • Epithelial Cells / metabolism
  • GTP-Binding Protein alpha Subunit, Gi2 / metabolism
  • HEK293 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Membrane Proteins / analysis
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Phosphoproteins / analysis
  • Phosphoproteins / chemistry
  • Phosphoproteins / metabolism*
  • RGS Proteins / metabolism
  • Zonula Occludens-1 Protein

Substances

  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Phosphoproteins
  • RGS Proteins
  • TJP1 protein, human
  • Zonula Occludens-1 Protein
  • GTP-Binding Protein alpha Subunit, Gi2