UQCRFS1

Cytochrome b-c1 complex subunit Rieske, mitochondrial: Component of the mitochondrial ubiquinol-cytochrome c reductase complex dimer (complex III dimer), which is a respiratory chain that generates an electrochemical potential coupled to ATP synthesis (PubMed:28673544). Incorporation of UQCRFS1 is the penultimate step in complex III assembly (By similarity).

Ubiquinol-Cytochrome C Reductase, Rieske Iron-Sulfur Polypeptide 1

Cytochrome b-c1 complex subunit Rieske, mitochondrial
Component of the ubiquinol-cytochrome c oxidoreductase, a multisubunit transmembrane complex that is part of the mitochondrial electron transport chain which drives oxidative phosphorylation (PubMed:31883641).
The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient over the inner membrane that drives transmembrane transport and the ATP synthase. The cytochrome b-c1 complex catalyzes electron transfer from ubiquinol to cytochrome c, linking this redox reaction to translocation of protons across the mitochondrial inner membrane, with protons being carried across the membrane as hydrogens on the quinol. In the process called Q cycle, 2 protons are consumed from the matrix, 4 protons are released into the intermembrane space and 2 electrons are passed to cytochrome c. The Rieske protein is a catalytic core subunit containing a [2Fe-2S] iron-sulfur cluster. It cycles between 2 conformational states during catalysis to transfer electrons from the quinol bound in the Q0 site in cytochrome b to cytochrome c1 (By similarity).
Incorporation of UQCRFS1 is the penultimate step in complex III assembly (PubMed:28673544).
Cytochrome b-c1 complex subunit 9
Component of the ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII). UQCRFS1 undergoes proteolytic processing once it is incorporated in the complex III dimer. One of the fragments, called subunit 9, corresponds to its mitochondrial targeting sequence (MTS). The proteolytic processing is necessary for the correct insertion of UQCRFS1 in the complex III dimer, but the persistence of UQCRFS1-derived fragments may prevent newly imported UQCRFS1 to be processed and assembled into complex III and is detrimental for the complex III structure and function.

Biological Process cellular respiration Source:ComplexPortal
Biological Process mitochondrial electron transport, ubiquinol to cytochrome c Source:GO_Central1 Publication
Biological Process mitochondrial respiratory chain complex III assembly Source:UniProtKB1 Publication
Biological Process respiratory electron transport chain Source:UniProtKB1 Publication

Mitochondrion inner membrane

Mitochondrial complex III deficiency, nuclear 10 (MC3DN10):
A form of mitochondrial complex III deficiency, a disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. MC3DN10 is an autosomal recessive form characterized by fetal bradycardia, poor feeding, hypotonia, hypertrophic cardiomyopathy, alopecia totalis, low mitochondrial complex III activity and lactic acidosis.

Mitochondrial matrix: 79-103
Helical: 104-140
Mitochondrial intermembrane: 141-274

Proteolytic processing is necessary for the correct insertion of UQCRFS1 in the complex III dimer. Several fragments are generated during UQCRFS1 insertion, most probably due to the endogenous matrix-processing peptidase (MPP) activity of the 2 core protein subunits UQCRC1/QCR1 and UQCRC2/QCR2, which are homologous to the 2 mitochondrial-processing peptidase (MPP) subunits beta-MPP and alpha-MPP respectively. The action of the protease is also necessary for the clearance of the UQCRFS1 fragments.