Cardiolipin
Cardiolipin (CL) is almost exclusively found in mitochondria with peroxisomes being the only other organelle with considerable amounts of CL. It is found predominantly in the inner membrane of mitochondria (up to 20% of total lipid) and is associated with many mitochondrial functions. Cardiac diseases have been linked to dysfunctions in mitochondrial cells due to a change in their CL pools. CL is composed of a glycerol head group and two phosphatidylglycerol backbones. The linoleic acid (18:2) species is the predominant species in the mammalian heart. Research has shown that the fatty acid composition of CL is dependent on tissue location and function. Several signaling pathways are directly dependent on CL for activation. PKC family proteins function in maintaining cardiac structure and function and some members of this family require CL for activation. It has even been proposed that CL functions as a signaling molecule, but research still needs to be done to elucidate the full extent of CL functions in human biology.
Dudek, J. Role of Cardiolipin in Mitochondrial Signaling Pathways. Front. Cell Dev. Biol. 2017. https://doi.org/10.3389/fcell.2017.00090