Regulation of G protein-coupled receptor activities by the platelet-endothelial cell adhesion molecule, PECAM-1

Biochemistry. 2008 Aug 26;47(34):9029-39. doi: 10.1021/bi8003846. Epub 2008 Aug 2.

Abstract

It is becoming increasingly evident that the cell-cell junction is a major signaling center. Here we show that the Galphaq/11 subunit of heterotrimeric G proteins forms a complex with platelet-endothelial cell adhesion molecule 1 (PECAM-1), a junctional protein that has been shown to be involved in mechanosignaling in endothelial cells. To understand the role of PECAM-1 in this complex, we determined the critical regions of PECAM-1 involved in this interaction. By expressing truncated forms of PECAM-1 in human embryonic kidney (HEK293) cells, we found that the cytoplasmic domain of PECAM-1 is not required for its association with Galphaq/11. Domain swapping of PECAM-1 with intracellular cell adhesion molecule 1 (ICAM-1), a protein that does not form a complex with Galphaq/11, provides evidence that the extracellular domain of PECAM-1 is critical for this interaction. This result also suggests that PECAM-1 does not directly interact with Galphaq/11. Coexpression of bradykinin receptor B2 (BKRB2), a Galphaq/11-coupled receptor, with PECAM-1 enhances formation of the PECAM-1-Galphaq/11 complex, suggesting an interaction between PECAM-1 and BKRB2. Co-immunoprecipitation experiments indicate that these two molecules indeed form a complex when expressed in HEK293 cells. Activation of ERK1/2 by bradykinin in HUVEC is enhanced when PECAM-1 expression is inhibited by transfection of small interference RNA against PECAM-1. Taken together, our results provide evidence of interaction of PECAM-1 with BKRB2 and of its possible role in regulating G protein-coupled receptor (GPCR) and G protein functions.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aluminum Compounds / pharmacology
  • Binding Sites / genetics
  • Bradykinin / pharmacology
  • Cell Line
  • Endothelial Cells / cytology
  • Endothelial Cells / drug effects
  • Endothelial Cells / metabolism*
  • Enzyme Activation / drug effects
  • Fluorides / pharmacology
  • GTP-Binding Protein alpha Subunits, Gq-G11 / genetics
  • GTP-Binding Protein alpha Subunits, Gq-G11 / metabolism*
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Mutation
  • Osmotic Pressure
  • Platelet Endothelial Cell Adhesion Molecule-1 / genetics
  • Platelet Endothelial Cell Adhesion Molecule-1 / metabolism*
  • Protein Binding / drug effects
  • RNA, Small Interfering / genetics
  • Receptor, Bradykinin B2 / genetics
  • Receptor, Bradykinin B2 / metabolism
  • Transfection

Substances

  • Aluminum Compounds
  • Platelet Endothelial Cell Adhesion Molecule-1
  • RNA, Small Interfering
  • Receptor, Bradykinin B2
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • GTP-Binding Protein alpha Subunits, Gq-G11
  • Fluorides
  • Bradykinin
  • aluminum fluoride