Ubiquinol-cytochrome c reductase, Rieske iron-sulfur polypeptide 1, also known as UQCRFS1, is a protein which in humans is encoded by the UQCRFS1 gene.
UQCRFS1 is a subunit of the respiratory chain protein (UQCR, Complex III or Cytochrome bc1 complex), which consists of the products of one mitochondrially encoded gene:
and ten nuclear genes:
After processing the cleaved leader sequence of the iron-sulfur protein is retained as subunit 9, giving 11 subunits from 10 genes.