AGK (Acylglycerol Kinase), also designated as MULK (multi-substrate lipid kinase), is a member of the AGK protein family and functions as a lipid kinase localized to the inner mitochondrial membrane. This protein exhibits a distinctive dual functionality. First, acting as a lipid kinase, it catalyzes the phosphorylation of monoacylglycerol and diacylglycerol to yield lysophosphatidic acid (LPA) and phosphatidic acid (PA), respectively, thereby participating in phospholipid metabolism and lipid-mediated signal transduction. Second, independent of its kinase activity, AGK serves as a core subunit of the TIM22 complex, where it is responsible for the translocation and insertion of multiple mitochondrial carrier proteins (e.g., ANT1) into the inner mitochondrial membrane.