Cell-surface-expressed T-cell antigen-receptor zeta chain is associated with the cytoskeleton.
The T-cell antigen receptor zeta chain plays an important role in coupling antigen recognition to several intracellular signal-transduction pathways. zeta chain can associate with certain protein tyrosine kinases and retains the capacity to transduce signals independently of the other receptor subunits. Thus, zeta chain could couple cell-surface-expressed T-cell antigen receptors to the intracellular signal-transduction apparatus by its association with various intracellular molecules in addition to tyrosine kinases. In the process of searching for zeta chain-associated molecules we observed that after lysis of resting T cells with Triton X-100, zeta chain is localized in the detergent-insoluble fraction, in addition to its presence in the detergent-soluble fraction. Treatment of T cells with cytochalasin B, an actin-depolymerizing agent, leads to the complete dissociation of zeta chain from the Triton-insoluble fraction, suggesting a linkage between zeta chain and the cytoskeletal matrix. We have also determined that cytoskeletal-associated zeta chain is expressed on the cell surface. Furthermore, a tyrosine-phosphorylated 16-kDa zeta chain was detected only in the Triton-insoluble cytoskeletal fraction of resting T cells. zeta chain also maintains its association with the cytoskeleton when expressed in COS cells, inferring that the cytoskeletal elements involved in this linkage may be ubiquitous. Finally, we have localized a 42-amino acid region in the intracytoplasmic domain of zeta chain, which is crucial for maximal interaction between zeta chain and the cytoskeleton. Anchorage of cell-surface-expressed zeta chain to the cytoskeleton in resting T cells may facilitate recycling of receptor complexes and/or allow the transduction of external stimuli into the cell.
Caplan
S
S
Lautenberg Center for General and Tumor Immunology, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Zeliger
S
S
Wang
L
L
Baniyash
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003571:Cytochalasin B / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000276:immunology*; D005260:Female; D006825:Hybridomas / Q000276:immunology; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011948:Receptors, Antigen, T-Cell / Q000032:analysis / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000032:analysis / Q000096:biosynthesis; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology; D014162:Transfection
D008565:Membrane Proteins; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; C054979:antigen T cell receptor, zeta chain; D003571:Cytochalasin B