FIGURE 2.

Roles of VMP1 in ER–membrane contacts. In WT cells, VMP1 competes with the inhibitory complex of PLN/SLN for interaction with SERCA to regulate the contacts of membrane structures (including mitochondria, endosome, and LDs) with ER. In VMP1-deficient cells, the interaction of SERCA with PLN/SLN leads to higher cytosolic Ca²⁺ levels and failure of the detachment of ER–membrane structure contacts. WIPI2 tethers IMs to the ER through interaction with ULK1/FIP200, and these interactions are reinforced by VMP1 depletion.