Endoplasmic reticulum-anchored protein that mediates the formation of contact sites between the endoplasmic (ER) and endosomes, mitochondria or Golgi through interaction with conventional- and phosphorylated-FFAT-containing organelle-bound proteins ( ). In addition, forms endoplasmic reticulum (ER)-lipid droplets (LDs) contacts through a direct protein-membrane interaction and participates in LDs homeostasis . The attachment mechanism involves an amphipathic helix that has an affinity for lipid packing defects present at the surface of LDs . Promotes migration of primary monocytes and neutrophils, in response to various chemokines .
Subcellular locations: Endoplasmic reticulum membrane
Localization to contact sites involving the endoplasmic reticulum and several organelles is regulated by interaction with proteins containing FFAT motif . Dynamically distributes between specific subdomains of the endoplasmic reticulum (ER): ER membranes in contact with lipid droplets (LDs) and the remainder of the ER .
Highly expressed in CD14(+) monocytes, and at lower levels in neutrophils. Does not show significant expression in B-cells or T-cells.