Structural domains of interleukin-2 receptor beta critical for signal transduction: kinase association and nuclear complex-formation.
The structural domains of interleukin-2 receptor beta (IL-2R beta) were examined, characterizing the protein domains, associated phosphoproteins and nuclear complexes of IL-2-induced signal transduction. A series of IL-2R beta cytoplasmic deletion mutants were constructed and transfected into a murine pre-B-cell line, Ba/F3. The proliferative response of characterized clones was determined. A minimal linear cytoplasmic sequence required for proliferation and a sequence motif (PQPLXP) needed along with Box1-Box2 for IL-2-induced proliferation were identified. Anti-phosphotyrosine Western-blot analysis of a stimulated biologically active clone showed several IL-2-induced tyrosylphosphorylated proteins with molecular masses ranging from 45 to 116 kDa. In vitro kinase studies of biologically active clone-receptor complexes showed a 116 kDa protein (p116) to be the major tyrosine-phosphorylated component. The presence of the p116 kinase in the receptor complex correlates with IL-2-induced proliferation. An IL-2-inducible p116 kinase has recently been characterized as a Jak kinase family member and named Jak3. Nuclear complexes were formed with the GRR oligomer only when the IL-2R beta mutant supported proliferation. This led us to conclude that Box1-Box2 and PQPLXP motifs associate with Jak3 and that this association is an essential element in the IL-2 signal-transduction pathway culminating in the formation of a nuclear complex.
Howard
O M
OM
Biological Carcinogenesis and Development Program, NCI-Frederick Cancer Research and Development Center, MD 21702.
Kirken
R A
RA
Garcia
G G
GG
Hackett
R H
RH
Farrar
W L
WL
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002455:Cell Division; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D008214:Lymphocytes; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D019000:Phosphotyrosine; D010957:Plasmids; D011494:Protein Kinases / Q000378:metabolism*; D015375:Receptors, Interleukin-2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism
D015375:Receptors, Interleukin-2; D019000:Phosphotyrosine; D014443:Tyrosine; D011494:Protein Kinases