Endoplasmic reticulum (ER)-anchored protein that mediates the formation of contact sites between the ER and endosomes via interaction with FFAT motif-containing proteins such as STARD3 or WDR44 (, ). Interacts with STARD3 in a FFAT motif phosphorylation dependent manner . Via interaction with WDR44 participates in neosynthesized protein export . Participates in the endoplasmic reticulum unfolded protein response (UPR) by inducing ERN1/IRE1 activity (, ). Involved in cellular calcium homeostasis regulation .
Subcellular locations: Endoplasmic reticulum membrane
Present in mitochondria-associated membranes that are endoplasmic reticulum membrane regions closely apposed to the outer mitochondrial membrane.
Ubiquitous. Isoform 1 predominates.