The CBP4 in S. cerevisiae is essential for the expression and activity of ubiquinol-cytochrome c reductase [1,2]. This family describes fungal and human proteins..

1: Characterization of CBP4, a new gene essential for the expression of ubiquinol-cytochrome c reductase in Saccharomyces cerevisiae. Crivellone MD; J Biol Chem 1994;269:21284-21292. PMID:8063753

2: Crosstalk between nuclear and mitochondrial genomes. Poyton RO, McEwen JE; Annu Rev Biochem 1996;65:563-607. PMID:8811190

3: A mutation in the human CBP4 ortholog UQCC3 impairs complex III assembly, activity and cytochrome b stability. Wanschers BF, Szklarczyk R, van den Brand MA, Jonckheere A, Suijskens J, Smeets R, Rodenburg RJ, Stephan K, Helland IB, Elkamil A, Rootwelt T, Ott M, van den Heuvel L, Nijtmans LG, Huynen MA; Hum Mol Genet. 2014;23:6356-6365. PMID:25008109