Reconstitution of the functional interleukin-5 receptor: the cytoplasmic domain of alpha-subunit plays an important role in growth signal transduction.
The receptor for interleukin-5 (IL-5) is composed of two distinct subunits, alpha and beta. The cDNAs that encode the mouse and human alpha-subunit were transfected into the mouse IL-3-dependent cell line, FDC-P1 expressing the mouse beta-chain intrinsically. The resulting transfectants became responsive to human and mouse IL-5, respectively. Using the mutant alpha-subunits, we found that the alpha-subunit as well as the beta-subunit participated in IL-5-mediated growth signal transduction. The FDC-P1 transfectants expressing the alpha-subunit which lacks its whole cytoplasmic domain did not respond to IL-5, though the interaction of the mutant alpha- and beta-subunits was not impaired. The transfectants expressing the alpha-subunit which lacks the C-terminal half of its cytoplasmic domain proliferated in the presence of IL-5. These results indicate that the transmembrane-proximal cytoplasmic portion of the alpha-subunit plays an important role in IL-5-mediated growth signal transduction.
Takaki
S
S
Department of Immunology, University of Tokyo, Japan.
Takatsu
K
K
D000818:Animals; D002460:Cell Line; D003593:Cytoplasm / Q000737:chemistry; D018076:DNA, Complementary / Q000235:genetics; D006128:Growth / Q000502:physiology; D006801:Humans; D051379:Mice; D018123:Receptors, Interleukin / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D053649:Receptors, Interleukin-5; D015398:Signal Transduction; D014162:Transfection
D018076:DNA, Complementary; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5