Identification of the second subunit of the murine interleukin-5 receptor: interleukin-3 receptor-like protein, AIC2B is a component of the high affinity interleukin-5 receptor.
Murine interleukin-5 (IL-5) binds to its receptor with high and low affinity. It has been shown that the high affinity IL-5 receptor (IL-5-R) is composed of at least two membrane protein subunits and is responsible for IL-5-mediated signal transduction. One subunit of the high affinity IL-5-R is a 60 kDa membrane protein (p60 IL-5-R) whose cDNA was isolated using the anti-IL-5-R monoclonal antibody (mAb), H7. This subunit alone binds IL-5 with low affinity. The second subunit does not bind IL-5 by itself, and is expressed not only on IL-5-dependent cell lines but also on an IL-3-dependent cell line, FDC-P1. Expression of the p60 IL-5-R cDNA in FDC-P1 cells, which do not bind IL-5, reconstituted the high affinity IL-5-R. We have characterized the second subunit of the IL-5-R by using another anti-IL-5-R mAb, R52.120, and the anti-IL-3-R mAb, anti-Aic-2. The anti-Aic-2 mAb down-regulated binding of IL-5 to an IL-5-dependent cell line, Y16. Both R52.120 and anti-Aic-2 mAbs recognized membrane proteins of 130-140 kDa expressed on FDC-P1 and Y16 cells. The R52.120 mAb recognized both murine IL-3-R (AIC2A) and its homologue (AIC2B) expressed on L cells transfected with suitable cDNAs. The high affinity IL-5-R was reconstituted on an L cell transfectant co-expressing AIC2B and p60 IL-5-R, whereas only the low affinity IL-5-R was detected on a transfectant co-expressing AIC2A and p60 IL-5-R.(ABSTRACT TRUNCATED AT 250 WORDS)
Takaki
S
S
Department of Biology, Kumamoto University Medical School, Japan.
Mita
S
S
Kitamura
T
T
Yonehara
S
S
Yamaguchi
N
N
Tominaga
A
A
Miyajima
A
A
Takatsu
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; D004247:DNA / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D015848:Interleukin-5 / Q000378:metabolism*; D051379:Mice; D011233:Precipitin Tests; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D018123:Receptors, Interleukin; D016185:Receptors, Interleukin-3 / Q000276:immunology / Q000378:metabolism*; D053649:Receptors, Interleukin-5; D014162:Transfection
D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; D015848:Interleukin-5; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D016185:Receptors, Interleukin-3; D053649:Receptors, Interleukin-5; D004247:DNA