This gene encodes a peripheral membrane protein associated with the mitochondrial inner membrane translocase, which functions in the import of proteins across the mitochondrial inner membrane and into the mitochondrial matrix. The encoded protein mediates binding of mitochondrial heat shock protein 70 to the translocase of inner mitochondrial membrane 23 (TIM23) complex. Expression of this gene is upregulated in kidney in a mouse model of diabetes. A mutation in this gene is associated with familial oncocytic thyroid carcinoma.