(A) Schematic depicting CHP1/GPAT4-catalyzed ER glycerolipid synthesis and the alternative peroxisomal pathway upon CHP1-GPAT4 loss. Under normal circumstances, CHP1 binds to and activates the major ER GPAT, (GPAT4), enabling the synthesis of membrane lipids and triacylglycerols at the endoplasmic reticulum. Upon CHP1 loss, peroxisomal GNPAT compensates for the loss of ER glycerolipid synthesis by generating acyl-DHAP, which in turn generates lysophosphatidic acid and glycerolipids.