Distal membrane-arm assembly complex protein 1 (DMAC1)

Distal membrane-arm assembly complex protein 1 (DMAC1), also known as transmembrane protein 261 (TMEM261) and C9orf123, is a small mitochondrial inner membrane protein required for the assembly and biogenesis of the distal membrane arm of mitochondrial respiratory complex I (NADH:ubiquinone oxidoreductase)[2][3][5]. Loss or knockout of DMAC1 leads to severe defects in complex I assembly and turnover of associated subunits, especially those comprising the ND4 and ND5 modules critical for functional respiratory chain activity[2][5]. DMAC1 is not itself a component of mature complex I, but functions as a transient assembly factor ushering in the correct formation of this essential respiratory enzyme[2][5]. It is not currently recognized as a classical therapeutic target, nor are there drugs or known biomarkers directly associated with it. Its dysfunction may contribute to mitochondrial disorders by impairing energy metabolism through defective complex I assembly[1][2][5].

Other names

DMAC1Transmembrane protein 261TMEM261C9orf123Chromosome 9 open reading frame 123Distal membrane arm assembly component 1