Composition of molecular cardiolipin species correlates with proliferation of lymphocytes

The mitochondrial phospholipid cardiolipin (CL) is required for oxidative phosphorylation. Oxidation of CL results in the disruption of CL-cytochrome c binding and the induction of apoptosis. Large variations in the acyl-chain residues of CL have been reported, but evidence as to whether these variants exert distinct biological effects has been limited. We have studied the acyl-chain composition of CL in lymphocytes, and found marked differences between highly and slowly proliferating cells. In fast growing cells, we detected a decreased number of double bonds, and a higher amount of C16 acyl-chain residues in CL, compared with slower growing cells. However, fewer C18 acyl-chain residues were found in CL from fast growing cells compared with slower proliferating cells. Our results suggest a functional link between acyl-chain composition of CL and cell proliferation.