The IL-2/IL-2 receptor system: involvement of a novel receptor subunit, gamma chain, in growth signal transduction.
We previously demonstrated the existence of a third component, p64, of IL-2 receptor (IL-2R), tentatively named the gamma chain of IL-2R. Our recent studies provided evidence suggesting that the gamma chain endows the beta chain of IL-2R with IL-2 binding ability. The gamma chain was detected in lymphoid transfectants of IL-2R beta cDNA, which showed the intermediate-affinity IL-2R, but not in nonlymphoid transfectants of IL-2R beta cDNA, which showed no IL-2 binding activity. The comparative study between two subclones of lymphoid MOLT4 transfectant of IL-2R beta cDNA demonstrated that the amount of the gamma chain coprecipitated with IL-2R beta was proportional to numbers of the IL-2 binding sites. These results suggest the possibility that the gamma chain associates with IL-2R beta and has an important role in formation of the intermediate-affinity IL-2R complex. On the other hand, we have also demonstrated the association of IL-2R beta with a certain tyrosine kinase, of which activation by IL-2 could be indispensable process at the initial pathway of signal transduction.
Sugamura
K
K
Department of Microbiology, Tohoku University School of Medicine, Sendai, Japan.
Takeshita
T
T
Asao
H
H
Kumaki
S
S
Ohbo
K
K
Ohtani
K
K
Nakamura
M
M
D000818:Animals; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D007376:Interleukin-2; D010446:Peptide Fragments; D015375:Receptors, Interleukin-2; D011505:Protein-Tyrosine Kinases