Golgi-associated cPLA2alpha regulates endothelial cell-cell junction integrity by controlling the trafficking of transmembrane junction proteins

Mol Biol Cell. 2009 Oct;20(19):4225-34. doi: 10.1091/mbc.e08-02-0210. Epub 2009 Aug 12.

Abstract

In endothelial cells specifically, cPLA2alpha translocates from the cytoplasm to the Golgi complex in response to cell confluence. Considering the link between confluence and cell-cell junction formation, and the emerging role of cPLA2alpha in intracellular trafficking, we tested whether Golgi-associated cPLA2alpha is involved in the trafficking of junction proteins. Here, we show that the redistribution of cPLA2alpha from the cytoplasm to the Golgi correlates with adherens junction maturation and occurs before tight junction formation. Disruption of adherens junctions using a blocking anti-VE-cadherin antibody reverses the association of cPLA2alpha with the Golgi. Silencing of cPLA2alpha and inhibition of cPLA2alpha enzymatic activity using various inhibitors result in the diminished presence of the transmembrane junction proteins VE-cadherin, occludin, and claudin-5 at cell-cell contacts, and in their accumulation at the Golgi. Altogether, our data support the idea that VE-cadherin triggers the relocation of cPLA2alpha to the Golgi and that in turn, Golgi-associated cPLA2alpha regulates the transport of transmembrane junction proteins through or from the Golgi, thereby controlling the integrity of endothelial cell-cell junctions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adherens Junctions / metabolism
  • Antibodies / immunology
  • Antibodies / pharmacology
  • Antigens, CD / immunology
  • Antigens, CD / metabolism
  • Blotting, Western
  • Cadherins / immunology
  • Cadherins / metabolism
  • Cells, Cultured
  • Claudin-5
  • Cytoplasm / enzymology
  • Endothelial Cells / cytology
  • Endothelial Cells / metabolism
  • Golgi Apparatus / drug effects
  • Golgi Apparatus / enzymology*
  • Group IV Phospholipases A2 / genetics
  • Group IV Phospholipases A2 / metabolism*
  • Humans
  • Membrane Proteins / metabolism*
  • Microscopy, Fluorescence
  • Occludin
  • Protein Transport / drug effects
  • RNA Interference
  • Tight Junctions / metabolism*

Substances

  • Antibodies
  • Antigens, CD
  • CLDN5 protein, human
  • Cadherins
  • Claudin-5
  • Membrane Proteins
  • OCLN protein, human
  • Occludin
  • cadherin 5
  • Group IV Phospholipases A2