Can convert acyl and alkyl dihydroxyacetone-phosphate (DHAP) into glycerolipids and ether lipids, respectively. Required for the biosynthesis of phosphatidic acid via the DHAP pathway, where it reduces 1-acyl DHAP to lysophosphatidic acid (LPA). Also has triacylglycerol (TAG) lipase activity. Involved in the mobilization of the non-polar storage lipids triacylglycerols (TAGs) from lipid particles by hydrolysis of TAGs. Lipolysis of TAG by AYR1 is essential for starvation-induced autophagy. Forms an NADPH-regulated cation-selective channel in the mitochondrial outer membrane. 1-hexadecanoyl-sn-glycero-3-phosphate + NADP(+) = 1-hexadecanoylglycerone 3-phosphate + H(+) + NADPH a 1-acylglycerone 3-phosphate + H(+) + NADPH = a 1-acyl-sn-glycero-3-phosphate + NADP(+) a triacylglycerol + H2O = a diacylglycerol + a fatty acid + H(+) Belongs to the short-chain dehydrogenases/reductases (SDR) family.