Calpain II colocalizes with detergent-insoluble rafts on human and Jurkat T-cells

Autor: Kathy Forrest, L.Kevin Overstreet, Lorri A. Morford, William H. Brooks, Barbara Logan, Thomas L. Roszman, Jens Goebel
Rok vydání: 2002
Předmět:
Zdroj: Biochemical and Biophysical Research Communications. 295:540-546
ISSN: 0006-291X
DOI: 10.1016/s0006-291x(02)00676-9
Popis: Calpain, a calcium-dependent cysteine protease, is known to associate with the T-cell plasma membrane and subsequently cleave a number of cytoskeletal-associated proteins. In this study, we report the novel observation that calpain II, but not calpain I, associates with membrane lipid rafts on human peripheral blood T-cells and Jurkat cells. Raft-associated calpain activity is enhanced with exogenous calcium and inhibited with calpeptin, a specific inhibitor of calpain activity. In addition, we demonstrate that calpain cleaves the cytoskeletal-associated protein, talin, during the first 30-min after cell stimulation. We propose that lipid raft associated-calpain II could function in early TCR signaling to facilitate immune synapse formation through cytoskeletal remodeling mechanisms. Hence, we demonstrate that the positioning of calpain II within T-cell lipid rafts strategically places it in close proximity to known calpain substrates that are cleaved during Ag-specific T-cell signaling and immune synapse formation.
Databáze: OpenAIRE