Molecular basis of the membrane-anchored and two soluble isoforms of the human interleukin 5 receptor alpha subunit.
By use of a 3' extension PCR strategy, cDNA clones were isolated spanning the transmembrane region and a complete cytoplasmic domain of the human interleukin 5 receptor alpha subunit (hIL5R alpha). These cDNAs differ from previously isolated clones encoding a soluble hIL5R alpha form by a sequence switch at position 1243. When expressed in COS-1 cells, only low-affinity binding of 125I-labeled human interleukin 5 was observed. Coexpression of the hIL5R beta chain led to a 2-fold increase in binding affinity. In addition, this same cloning strategy allowed us to identify a putative second soluble isoform of hIL5R alpha. Genomic data revealed that the two soluble variants arise from either a "normal" splicing event or from the absence of splicing, whereas synthesis of the membrane-anchored form requires alternative splicing.
Tavernier
J
J
Roche Research Gent, Belgium.
Tuypens
T
T
Plaetinck
G
G
Verhee
A
A
Fiers
W
W
Devos
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002462:Cell Membrane / Q000276:immunology; D004247:DNA / Q000235:genetics*; D005260:Female; D015698:Genomic Library; D006801:Humans; D015848:Interleukin-5 / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D010920:Placenta / Q000502:physiology; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D011971:Receptors, Immunologic / Q000235:genetics* / Q000378:metabolism; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5; D014162:Transfection
D015848:Interleukin-5; D046911:Macromolecular Substances; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D053649:Receptors, Interleukin-5; D004247:DNA