Colocalization of MCT1, CD147, and LDH in mitochondrial inner membrane of L6 muscle cells: evidence of a mitochondrial lactate oxidation complex.
Level 5 - mechanism / opinion, no new human data
In vitro bench study using a rat skeletal muscle cell line.
PubMed 16434551 · doi:10.1152/ajpendo.00594.2005
What was done
Researchers examined the intracellular localization and protein-protein interactions of lactate dehydrogenase (LDH), monocarboxylate transporter 1 (MCT1), and its chaperone CD147 in a rat-derived L6 skeletal muscle cell line using confocal laser-scanning microscopy, subcellular fractionation with Western blotting, and co-immunoprecipitation.
What was found
The abstract reports no quantitative numerical values. Confocal microscopy demonstrated that LDH, MCT1, and CD147 colocalized with the mitochondrial reticulum. Western blotting showed abundance of cytochrome oxidase (COX), NADH dehydrogenase, LDH, MCT1, and CD147 in isolated mitochondrial fractions. Immunoblotting after immunoprecipitation confirmed physical interactions among COX, MCT1, and CD147 in mitochondria.
Why it matters
These findings provide biochemical evidence for a mitochondrial lactate oxidation complex linked to the electron transport chain, offering a structural mechanism for intracellular lactate shuttling and direct mitochondrial lactate catabolism in muscle.
Limits
The study was conducted entirely in an immortalized rat cell line (L6 cells) in vitro, without in vivo physiological validation or human tissue testing. The abstract provides no quantitative data, effect sizes, or functional metabolic flux measurements.
Cited by
- supports Lactate transporters are located in plasma membranes and within the mitochondrial reticulum as lactate/pyruvate transporters.