Caseinolytic Peptidase P (CLPP)

ATP-dependent proteases were first identified in E. coli. Bross et al. (1995) stated that one of these, called ClpAP or Ti, consists of a regulatory unit, ClpA, with chaperone characteristics and an ATPase domain, and a proteolytic subunit, ClpP. This protease is involved in ATP-dependent degradation of abnormal proteins. Many mutations, e.g., those resulting in medium-chain acyl-CoA dehydrogenase deficiency, cause impaired folding of proteins. Impaired folding results in premature degradation of the mutant polypeptides. The open reading frame encodes a 277-amino acid precursor polypeptide. Northern blot analysis showed high relative expression levels of CLPP mRNA in skeletal muscle, intermediate levels in heart, liver, and pancreas, and low levels in brain, placenta, lung, and kidney.