Leupeptin-binding Site(s) in the Mammalian Multicatalytic Proteinase Complex
Overview
Authors
Affiliations
The multicatalytic proteinase (MCP) complex is a major nonlysosomal proteinase which plays an important role in non-lysosomal pathways of protein degradation and which has recently been implicated in antigen processing. The mammalian MCP complex is composed of more than 20 different types of polypeptide, but it is not yet clear which of these components are responsible for its proteolytic activities. The complex has at least three distinct types of proteolytic activity. One of these, the so-called 'trypsin-like' activity, which involves cleavage on the carboxy side of basic amino acid residues, can be selectively and completely inhibited by peptidyl arginine aldehydes (such as leupeptin and antipain), and is also the most sensitive to inhibition by thiol-reactive reagents. In the present study N-[ethyl-1-14C]ethylmaleimide has been used to specifically label thiol groups protected by leupeptin binding. The results suggest that one or two polypeptide components within the complex can be protected against modification by N-ethylmaleimide. These components may be responsible for the 'trypsin-like' activity of the complex or may be adjacent to the catalytic component(s) and play an important role in substrate binding.
Kantyka T, Rawlings N, Potempa J Biochimie. 2010; 92(11):1644-56.
PMID: 20558234 PMC: 2952067. DOI: 10.1016/j.biochi.2010.06.004.
Scott C, Kruse K, Schmidt B, Perlmutter D, McCracken A, Brodsky J Mol Biol Cell. 2007; 18(10):3776-87.
PMID: 17634286 PMC: 1995736. DOI: 10.1091/mbc.e07-01-0034.
Barrionuevo P, Beigier-Bompadre M, de la Barrera S, Alves-Rosa M, Fernandez G, Palermo M Clin Exp Immunol. 2001; 125(2):251-7.
PMID: 11529917 PMC: 1906131. DOI: 10.1046/j.1365-2249.2001.01609.x.
Arendt C, Hochstrasser M Proc Natl Acad Sci U S A. 1997; 94(14):7156-61.
PMID: 9207060 PMC: 23776. DOI: 10.1073/pnas.94.14.7156.
Djaballah H, ROWE A, Harding S, Rivett A Biochem J. 1993; 292 ( Pt 3):857-62.
PMID: 8318014 PMC: 1134193. DOI: 10.1042/bj2920857.