MICOS complex subunit MIC19

CHCHD3 encodes MIC19, a core component of the mitochondrial inner membrane organizing system (MICOS) complex. It functions to maintain crista junctions, inner membrane architecture, and mitochondrial–outer membrane contact sites, thereby preserving mitochondrial structural integrity and cristae morphology (UniProt: Q9NX63). The protein also acts as a transcription factor, repressing BAG1 gene expression.

CHCHD3 is expressed in mitochondria-rich tissues and localizes to the mitochondrial inner membrane as part of the MICOS complex, which is essential for proper mitochondrial function and bioenergetics (UniProt: Q9NX63). No explicit disease associations are documented in the primary UniProt record.

CHCHD3 is associated with Alzheimer's Disease and shows reduced abundance in affected tissue. Analysis of post-mortem AD brain compared to age-matched controls by TMT-labeled proteomics detected a mean log2 fold-change of −0.52, indicating down-regulation in AD (Chaparral AD proteomics). This reduction may reflect compromised mitochondrial structural maintenance and energy metabolism in AD pathology, consistent with emerging evidence of mitochondrial dysfunction in neurodegeneration.