Calcium Signaling through the β2-Cytoplasmic Domain of LFA-1 Requires Intracellular Elements of the T Cell Receptor Complex

• Published in: The Journal of biological chemistry 2001-11, Vol.276 (46), p.42945
• Main Authors: Pinar Sirim, Lutz Zeitlmann, Bettina Kellersch, Christine S. Falk, Dolores J. Schendel, Waldemar Kolanus
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M103224200

The β 2 integrin LFA-1 is an important cell-cell adhesion receptor of the immune system. Evidence suggests that the molecule also participates in signaling and co-stimulatory function. We show here that clustering of the intracellular domain of the β 2 chain but not of the α L - or β 1 -cytoplasmic domains, respectively, triggers intracellular Ca 2+ mobilization in Jurkat cells. A β 2 -specific NP X F motif, located in the C-terminal portion of the β 2 tail, is required for Ca 2+ signaling, and we show that this motif is important for the induction of allo-specific target cell lysis by cytotoxic T cells in vitro . Significantly, the Ca 2+ -signaling capacity of the β 2 integrin is abrogated in T cells that do not express the T cell receptor but may be reconstituted by co-expression of the T cell receptor-ζ chain. Our data suggest a specific function of the cytoplasmic domain of the β 2 integrin chain in T cell signaling.