FIGURE 1.

Cardiolipin synthesis and remodeling pathway. CL synthesis is initiated by the formation of cytidine diphosphate diacylglycerol (CDP-DAG) from PA by the transfer of CDP to PA from cytidine triphosphate (CTP). Both Cds1 and Tam41 can catalyze this reaction, but in yeast, the majority of CL is made from CDP-DAG supplied by Tam41. The rate-limiting production of phosphatidylglycerol phosphate (PGP) by the addition of glycerol 3-phosphate (G-3-P) to CDP-DAG is catalyzed by PGP synthase (Pgs1). After the removal of phosphate from PGP by Gep4, phosphatidylglycerol (PG) is then condensed with CDP-DAG by CL synthase (Crd1) to form premature CL (CLp). The de novo premature CL lacks the abundance of unsaturated fatty acyl species in mature CL (CLm), and it undergoes fatty acyl remodeling by the actions of CL deacylase 1 (Cld1) and Taz1. First, premature CL is deacylated by Cld1 to generate MLCL (which has only three acyl chains), which is then reacylated by Taz1 by the transfer of acyl chains from PC or PE to produce mature CL.