IL-1H, an interleukin 1-related protein that binds IL-18 receptor/IL-1Rrp.
IL-18, or IGIF (interferon-gamma inducing factor), is an IL-1-related, pro-inflammatory cytokine, which plays a pivotal role in systemic and local inflammation. We have identified and characterized IL-1H, a novel IL-1-related molecule. IL-1H appears to be expressed in most tissues with relatively high levels in testis, thymus and uterus. The IL-1H transcripts were stimulated by phorbol ester (PMA) in human cell lines (A431, THP-1 and KG-1) and peripheral blood mononuclear cells (HPBMC) and dendritic cells (NHDC). The protein sequence of IL-1H is mostly related to IL-1ra with a similarity of 36%. A short form of IL-1H was identified, and lacks a 40-amino acid segment in the amino-terminal region of the protein. When expressed in mammalian cells, two secreted polypeptides of IL-1H were identified: an uncleaved and a cleaved form starting with amino acid Val-46. Furthermore, IL-1H binds the IL-18 receptor, but not the IL-1 receptor. These findings suggest that IL-1H may be another ligand for the IL-18 receptor and a new player in the inflammatory and immune responses mediated by the IL-18/IL-18R axis.
Pan
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G
Department of Endocrinology, Genentech, Inc., 1 DNA Way, South San Francisco, CA, 94080, USA.  jgpan@gene.com
Risser
P
P
Mao
W
W
Baldwin
D T
DT
Zhong
A W
AW
Filvaroff
E
E
Yansura
D
D
Lewis
L
L
Eigenbrot
C
C
Henzel
W J
WJ
Vandlen
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D002460:Cell Line; D003001:Cloning, Molecular; D006224:Cricetinae; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D053727:Interleukin-18 Receptor alpha Subunit; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018123:Receptors, Interleukin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D053724:Receptors, Interleukin-18; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014018:Tissue Distribution; D014162:Transfection
D017931:DNA Primers; C421843:IL-1H receptor; C508572:IL18R1 protein, human; D053727:Interleukin-18 Receptor alpha Subunit; D011506:Proteins; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053724:Receptors, Interleukin-18; D011994:Recombinant Proteins; D013755:Tetradecanoylphorbol Acetate