Novel T cell antigen 4-1BB associates with the protein tyrosine kinase p56lck1.
4-1BB is a 30-kDa inducible T cell Ag, and is expressed predominantly as a 55-kDa dimer on both CD4+ and CD8+ T lymphocytes. The cytoplasmic tail of 4-1BB contains the sequence Cys-Arg-Cys-Pro, which is similar to the sequence Cys-X-Cys-Pro, which mediates the binding of the CD4 and CD8 molecules to the protein tyrosine kinase p56lck. An anti-4-1BB mAb, 53A2, was used to determine whether 4-1BB may associate with p56lck. The 53A2 mAb specifically recognized 4-1BB on a CD8+ T cell line, CTLL-2, and coimmunoprecipitated a 56-kDa protein along with 4-1BB. Peptide mapping indicated that the 56-kDa phosphoprotein was identical to p56lck. The coimmunoprecipitation of p56lck with 4-1BB also occurred in nonlymphoid cells such as insect (Sf-21) and HeLa cells when the two recombinant proteins were coexpressed. Analysis of mutant p56lck recombinant proteins showed that two cysteine residues critical for p56lck-CD4 (or -CD8) complex formation are also required for the p56lck-4-1BB interaction. These studies establish that 4-1BB physically associates with p56lck.
Kim
Y J
YJ
Department of Microbiology and Immunology, Walther Oncology Center, Indiana University School of Medicine, Indianapolis 46202.
Pollok
K E
KE
Zhou
Z
Z
Shaw
A
A
Bohlen
J B
JB
Fraser
M
M
Kwon
B S
BS
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism*; D002460:Cell Line; D003545:Cysteine / Q000737:chemistry; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010766:Phosphorylation; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D046911:Macromolecular Substances; D010455:Peptides; D011994:Recombinant Proteins; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D003545:Cysteine