The function of TTC19 (tetratricopeptide repeat domain 19, ENSG00000011295) is as follows. Required for the preservation of the structural and functional integrity of mitochondrial respiratory complex III by allowing the physiological turnover of the Rieske protein UQCRFS1 (PubMed:21278747, PubMed:28673544). Involved in the clearance of UQCRFS1 N-terminal fragments, which are produced upon incorporation of UQCRFS1 into the complex III and whose presence is detrimental for its catalytic activity (PubMed:28673544). {ECO:0000269|PubMed:21278747, ECO:0000269|PubMed:28673544}.