GSBS Student Publications

Title

Cathepsin B cleavage of Ii from class II MHC alpha- and beta-chains

UMMS Affiliation

Graduate School of Biomedical Sciences; Department of Pharmacology

Date

6-1-1991

Document Type

Article

Medical Subject Headings

*Antigens, Differentiation, B-Lymphocyte; Cathepsin B; Cathepsin D; Cell Line; Histocompatibility Antigens Class II; Humans; Leupeptins

Disciplines

Life Sciences | Medicine and Health Sciences

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 alpha- and beta-chains at the time of peptide charging. We examined the cleavage and release of Ii from class II MHC alpha/beta 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 alpha- and beta-chains. Cathepsin B digested Ii from alpha- and beta-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.

Rights and Permissions

Citation: J Immunol. 1991 Jun 1;146(11):3877-80.

Related Resources

Link to Article in PubMed

Journal Title

Journal of immunology (Baltimore, Md. : 1950)

PubMed ID

2033257