MPC1 encodes the mitochondrial pyruvate carrier 1, a membrane protein that mediates pyruvate uptake into mitochondria, maintaining metabolic balance between glycolysis and oxidative phosphorylation 12345. MPC1 functions as part of a heterodimeric complex with MPC2, with transmembrane helices forming the pyruvate transport channel 65. The complex undergoes asymmetric conformational changes during substrate binding and translocation across the inner mitochondrial membrane 65. MPC1 has critical roles in diverse metabolic contexts. In nonalcoholic fatty liver disease, MPC1 expression correlates with hepatic lipid deposition; MPC1 reduction decreases liver lipid accumulation through enhanced lactylation of fatty acid synthase at the K673 site 7. In cardiac tissue, decreased MPC expression during heart failure represents altered pyruvate-lactate axis metabolism; MPC overexpression attenuates hypertrophy while MPC ablation induces cardiomyocyte hypertrophy 8. In cancer immunotherapy, enhancing MPC-dependent oxidative phosphorylation revitalizes terminally exhausted CD8+ T cells 9. Pathogenic MPC1 variants cause rare autosomal recessive mitochondrial pyruvate carrier deficiency, characterized by developmental delay, microcephaly, and increased serum lactate/pyruvate 10. Alternative substrates like glutamine and beta-hydroxybutyrate can partially compensate for pyruvate uptake loss 10.