Ubiquinol-cytochrome c reductase complex assembly factor 6 (UQCC6)

Ubiquinol-cytochrome c reductase complex assembly factor 6 (UQCC6, also known as BRAWNIN) is a highly conserved, nuclear-encoded mitochondrial microprotein required for the assembly and stability of the mitochondrial respiratory chain complex III (cytochrome b-c1 complex), essential for electron transport and oxidative phosphorylation. UQCC6/BRAWNIN is localized to the inner mitochondrial membrane, where it functions as an early assembly factor of complex III, regulating mitochondrial ATP production in response to cellular energy status. Depletion or mutation of UQCC6 results in impaired complex III formation, reduced ATP production, metabolic dysfunction (including lactic acidosis), growth retardation, and early lethality in model organisms. UQCC6 expression is tightly regulated by the energy-sensing AMPK-PGC1α pathway, linking it to bioenergetic adaptation and potentially broader metabolic and immune functions[1][2][3][8].

Other names

BRAWNINBRProtein BRAWNINC12orf73FLJ13975DKFZp547P055uncharacterized protein C12orf73

Not applicable (no current drugs); future targeting would likely involve modulation of complex III assembly or mitochondrial function