Cathepsin B cleavage of Ii from class II MHC α- and β-chains

Victor Reyes, Shan Lu, Robert E. Humphreys

Research output: Contribution to journalArticle

68 Citations (Scopus)

Abstract

Class II MHC-associated invariant chain (Ii) might regulate binding of digested peptides to the Ag binding site (desetope) of class II MHC proteins by directly or allosterically blocking that site until cleavage and release of Ii from MHC α- and β-chains at the time of peptide charging. We examined the cleavage and release of Ii from class II MHC α/β/Ii trimers by cathepsin B, which has been shown by others to colocalize with class II MHC molecules in intracellular compartments and to generate antigenic peptide fragments. Cathepsin B at pH 5.0 cleaved and released Ii from class II MHC α- and β-chains. Cathepsin B digested Ii from α- and β-chains in a dose-dependent fashion, yielding 23-, 21-, and 10-kDa fragments. Blockage of cathepsin B activity with leupeptin restored the 2D(nonequilibrium pH gradient gel electrophoresis/SDS) PAGE patterns of Ii and sialic acid-derivatized forms of Ii seen without the protease. The fragmentation pattern of cathepsin D treatment was different from that of cathepsin B, yielding 25-kDa intermediates.

Original languageEnglish (US)
Pages (from-to)3877-3880
Number of pages4
JournalJournal of Immunology
Volume146
Issue number11
StatePublished - Jun 1 1991
Externally publishedYes

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Cathepsin B
Cathepsin D
Peptides
Peptide Fragments
Proton-Motive Force
N-Acetylneuraminic Acid
Electrophoresis
Polyacrylamide Gel Electrophoresis
Peptide Hydrolases
Gels
Binding Sites
Proteins

ASJC Scopus subject areas

  • Immunology

Cite this

Cathepsin B cleavage of Ii from class II MHC α- and β-chains. / Reyes, Victor; Lu, Shan; Humphreys, Robert E.

In: Journal of Immunology, Vol. 146, No. 11, 01.06.1991, p. 3877-3880.

Research output: Contribution to journalArticle

Reyes, V, Lu, S & Humphreys, RE 1991, 'Cathepsin B cleavage of Ii from class II MHC α- and β-chains', Journal of Immunology, vol. 146, no. 11, pp. 3877-3880.
Reyes, Victor ; Lu, Shan ; Humphreys, Robert E. / Cathepsin B cleavage of Ii from class II MHC α- and β-chains. In: Journal of Immunology. 1991 ; Vol. 146, No. 11. pp. 3877-3880.
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