Cardiolipin is a mitochondrion-specific phospholipid found in both the mitochondrial inner and outer membranes6 Many studies speculate that cardiolipin is a likely player in mitochondrial apoptosis. In a study done by R Lee et al., it was found that during apoptosis, cardiolipin in the outer membrane of the mitochondria increased from 10% to 30% saturation. Finding that cardiolipin concentration in the outer mitochondrial membrane increased during apoptosis (as well as knowing the function that PLS3 plays in mitochondrial apoptotic effects) clued Lee in to the fact that PLS3 may have effects on this cardiolipin membrane redistribution. Lee’s study looked into the consequences of cardiolipin redistribution in the mitochondria and found that cardiolipin plays a critical role in proteins that are involved with oxidative respiration (such as ATP synthase), which in turn affects ATP production. In Lee's experiment determining the effect of cardiolipin deprivation on cells, he studied an infected yeast mutant that lacked a cardiolipin creating enzyme, and found that although it was viable, the yeast was "moderately deficient in mitochondrial energy transforming machinery."
It was subsequently deduced that PLS3 is an effector for the redistribution of cardiolipin from the inner to outer mitochondrial membrane. Thus, when PLS3 flips cardiolipin across the inner to outer membrane of the mitochondria, the oxidative phosphorylation induced is greatly disturbed. It was deduced experimentally that a lack of proper oxidative phosphorylation is directly linked with mitochondrial apoptosis. Thus, this PLS3-induced redistribution of cardiolipin during apoptosis has major effects on mitochondrial function.
Although the results of the experiments above are very intriguing and shed light on what was once a mystery, there have been only a few experiments that have targeted PSL3. And, furthermore, in a majority of the experiments and studies that were reviewed, it is evident that there is some doubt in the experimental findings 789
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