IL-2 receptor signaling through the Shb adapter protein in T and NK cells.
Interleukin-2 induces heterodimerization of the IL-2 receptor beta and gamma subunits. This study addresses a role of the Shb adapter protein in IL-2 receptor signaling in T and NK cells. The IL-2Rbeta and gamma chains were found to co-immunoprecipitate with Shb, when each alone was co-expressed with Shb in COS cells. Using fusion proteins, the Shb SH2 domain was found to associate in a phosphotyrosine-dependent manner with the IL-2 receptor beta and gamma subunits upon IL-2 stimulation in primary T cells and the NK cell line NK-92. The main binding site of the Shb SH2 domain was phosphorylated Tyr-510 in the IL-2Rbeta chain. Shb was also phosphorylated upon IL-2 stimulation when overexpressed together with IL-2Rbeta (in pre-B cells, which express the gamma chain constitutively). These cells were also less apoptotic in the presence of IL-2 than cells overexpressing a mutant Shb (with a defect SH2 domain) or cells expressing a mutant IL-2Rbeta, with the Shb binding sites mutated to phenylalanine (Y392F, Y510F). JAK1 and JAK3 were also found to associate with Shb, but in contrast to the Shb-IL-2 receptor association, JAK1 and 3 appear to associate with the proline-rich regions of Shb. In conclusion, Shb links the IL-2 receptor to other signaling proteins and mediates the regulation of apoptosis in the presence of IL-2.
Lindholm
Cecilia K
CK
Department of Medical Cell Biology, Uppsala University, Biomedicum, Box 571, S-75123 Uppsala, Sweden. Cecilia.Lindholm@medcellbiol.uu.se
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis; D001665:Binding Sites; D019002:CD56 Antigen / Q000378:metabolism; D019556:COS Cells; D002455:Cell Division; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D006801:Humans; D053613:Janus Kinase 1; D053616:Janus Kinase 3; D007694:Killer Cells, Natural / Q000378:metabolism*; D009154:Mutation; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry; D010649:Phenylalanine / Q000378:metabolism; D010766:Phosphorylation; D011233:Precipitin Tests; D011392:Proline / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D019002:CD56 Antigen; D010455:Peptides; D011518:Proto-Oncogene Proteins; D015375:Receptors, Interleukin-2; D011993:Recombinant Fusion Proteins; C490081:SHB protein, human; D014443:Tyrosine; D010649:Phenylalanine; D004247:DNA; D011392:Proline; D011505:Protein-Tyrosine Kinases; C507904:JAK1 protein, human; C507933:JAK3 protein, human; D053613:Janus Kinase 1; D053616:Janus Kinase 3