UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Selective interaction of LAT (linker of activated T cells) with the open-active form of Lck in lipid rafts reveals a new mechanism for the regulation of Lck in T cells.

Kabouridis, PS; (2003) Selective interaction of LAT (linker of activated T cells) with the open-active form of Lck in lipid rafts reveals a new mechanism for the regulation of Lck in T cells. Biochem J , 371 (Pt 3) pp. 907-915. 10.1042/BJ20021578.

Full text not available from this repository.

Abstract

In T cells, the lipid raft-associated Lck is strongly tyrosine phosphorylated and has reduced enzymic activity in contrast with the detergent-soluble pool, which has substantial activity. Lck tagged at the C-terminus (Lck/V5-His) was efficiently captured by epitope-specific reagents from the detergent-soluble fraction but not from lipid rafts. Binding was restored following urea denaturation, suggesting that Lck/V5-His is in a 'closed' conformation in these domains. In agreement with this hypothesis, the Tyr(505) --> Phe/V5-His and Arg(154) --> Lys/V5-His mutants, which disrupt the SH2-Tyr(505) intramolecular interaction, were efficiently precipitated from lipid rafts. In contrast to Lck, Fyn/V5-His was precipitated equally well from both fractions. In the LAT(linker of activated T cells)-deficient J.CaM2 cells, Tyr(505) phosphorylation of raft-associated Lck was reduced whereas its enzymic activity was elevated. This correlated with decreased levels of raft-localized Csk (C-terminal Src kinase) kinase. Increased tyrosine phosphorylation of Lck was restored in LAT-reconstituted J.CaM2 cells suggesting that LAT negatively regulates Lck activity in lipid rafts. Co-immunoprecipitation experiments from Tyr(505) --> Phe/V5-His-expressing cells revealed that LAT preferentially interacts with the 'open' form of Lck in T cell raft domains. These results demonstrate that, unlike the non-raft pool, Lck in lipid rafts has a 'closed'-inactive structure, and that LAT plays a role in maintaining this conformation, possibly by facilitating critical associations within lipid rafts via its capacity to interact with the 'open' form of the kinase.

Type: Article
Title: Selective interaction of LAT (linker of activated T cells) with the open-active form of Lck in lipid rafts reveals a new mechanism for the regulation of Lck in T cells.
Location: England
DOI: 10.1042/BJ20021578
Keywords: Adaptor Proteins, Signal Transducing, Base Sequence, Blotting, Western, Carrier Proteins, DNA Primers, Humans, Jurkat Cells, Lipid Metabolism, Membrane Proteins, Phosphoproteins, Phosphorylation, Precipitin Tests, Protein Binding, Protein Conformation, T-Lymphocytes, Tyrosine
UCL classification: UCL > School of Life and Medical Sciences
UCL > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > School of Life and Medical Sciences > Faculty of Medical Sciences > Medicine (Division of)
URI: http://discovery.ucl.ac.uk/id/eprint/1319195
Downloads since deposit
0Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item