Identification and Characterization of Two Distinct Truncated Forms of gp130 and a Soluble Form of Leukemia Inhibitory Factor Receptor α-Chain in Normal Human Urine and Plasma

• Published in: The Journal of biological chemistry Vol. 273; no. 17; pp. 10798 - 10805
• Main Authors: Zhang, Jian-Guo, Zhang, Yu, Owczarek, Catherine M., Ward, Larry D., Moritz, Robert L., Simpson, Richard J., Yasukawa, Kiyoshi, Nicola, Nicos A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 24.04.1998
• Subjects: Amino Acid Sequence; Antigens, CD - blood; Antigens, CD - metabolism; Antigens, CD - urine; Chromatography, Gel; Cytokine Receptor gp130; Growth Inhibitors; Humans; Interleukin-6; Leukemia Inhibitory Factor; Leukemia Inhibitory Factor Receptor alpha Subunit; Lymphokines - metabolism; Membrane Glycoproteins - blood; Membrane Glycoproteins - metabolism; Membrane Glycoproteins - urine; Molecular Sequence Data; Receptors, Cytokine - blood; Receptors, Cytokine - metabolism; Receptors, OSM-LIF; Recombinant Proteins - blood; Recombinant Proteins - metabolism; Recombinant Proteins - urine; Signal Transduction; Solubility
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.17.10798

Leukemia inhibitory factor (LIF) is a polyfunctional cytokine known to require at least two distinct receptor components (LIF receptor α-chain and gp130) in order to form a high affinity, functional receptor complex. In this report, we present evidence that there are two distinct truncated forms of gp130 in normal human urine and plasma: a large form with a molecular weight of approximately 100,000, which is similar to a previously described form of soluble gp130 in human serum, and a previously undescribed small form with a molecular weight of approximately 50,000. Using a panel of monoclonal antibodies raised against the extracellular domain of human gp130, we were able to show that the small form of the urinary gp130 probably contained only the hemopoietin domain. Both forms of gp130 bound LIF specifically and were capable of forming heterotrimeric complexes with soluble human LIF receptor α-chain in the presence of human LIF. In addition to the soluble forms of gp130, a soluble form of LIF receptor α-chain was also detected in human urine and plasma.