The protein encoded by this gene plays a role in mitochondrial translation termination, and is thought to be a release factor that is involved in the dissociation of the complete protein from the final tRNA, the ribosome, and the cognate mRNA. This protein acts upon UAA and UAG stop codons, but has no in vitro activity against UGA, which encodes tryptophan in human mitochondrion, or, the mitochondrial non-cognate stop codons, AGA and AGG. This protein shares sequence similarity to bacterial release factors. Pseudogenes of this gene are found on chromosomes 4, 8, and 11. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2014].