Differential reduction in cardiac and liver monolysocardiolipin acyltransferase-1 and reduction in cardiac and liver tetralinoleoyl-cardiolipin in the α-subunit of trifunctional protein heterozygous knockout mice

The contribution of alpha-subunit of trifunctional protein (alpha TFP) to cardiolipin (CL) (diphosphatidylglycerol) remodelling and mitochondrial supercomplex formation was examined in heart and liver mitochondria from wild-type (WT) and alpha TFP heterozygous knockout [Mtpa(+/-)] mice. Mtpa(+/-) mouse heart and liver exhibited an approximate 55% and 50% reduction in alpha TFP protein expression compared with WT respectively. Monolysocardiolipin (MLCL) acyltransferase (MLCL AT)-1 protein derived from alpha TFP was reduced by 30% in Mtpa(+/-) mouse heart but not in liver compared with WT. In vitro acylation of MLCL was significantly reduced in heart but not in liver mitochondria of Mtpa(+/-) mice compared with WT. CL mass was reduced and significant reductions in linoleate-containing CL species, in particular tetralinoleoyl-CL (L-4-CL) and trilinoleoyl-CL (L3-MLCL) species, were observed in heart and liver mitochondria of Mtpa(+/-) mice compared with WT. Cardiac and liver mitochondrial supercomplex assembly and NADH dehydrogenase (complex I) activity within these supercomplexes were unaltered in both Mtpa(+/-) mouse heart and Mtpa(+/-) mouse liver compared with WT. The results indicate that alpha TFP may modulate CL molecular species composition in murine heart and liver. In addition, L-4-CLmight not be an essential requirement for mitochondrial supercomplex assembly.