ATP-dependent specificity component of the Clp protease complex. Hydrolyzes ATP (PubMed:28874591). Targets specific substrates for degradation by the Clp complex (PubMed:11923310, PubMed:22710082). Can perform chaperone functions in the absence of CLPP. Enhances the DNA-binding activity of TFAM and is required for maintaining a normal mitochondrial nucleoid structure (PubMed:22841477). ATP-dependent unfoldase that stimulates the incorporation of the pyridoxal phosphate cofactor into 5-aminolevulinate synthase, thereby activating 5-aminolevulinate (ALA) synthesis, the first step in heme biosynthesis (PubMed:28874591). Important for efficient erythropoiesis through up-regulation of heme biosynthesis (PubMed:25957689, PubMed:28874591).