Recombinant Rat CNTFR alpha Protein

The high-affinity CNTF receptor complex, which mediates the biological action of CNTF, contains three proteins: the ligand-binding a subunit (CNTF R alpha) and the two signal-transducing proteins LIF R beta and gp130. Whereas LIF R beta and gp130 are widely expressed in many cell types, the expression of CNTF R alpha is restricted to the central and peripheral nervous systems. cDNAs encoding CNTF R alpha have been isolated from both human and rat and were shown to share 94% amino acid (aa) sequence identity. Rat CNTF R alpha cDNA encodes a 372 amino acid residue precursor protein that apparently has a 22 aa residue signal peptide and five potential glycoslyation sites. CNTF R alpha differs from other cytokine receptors in that it lacks transmembrane and cytoplasmic domains and is anchored to cell membranes by a glycosylphosphatidylinositol (GPI) linkage. Similar to other GPI-linked proteins, soluble CNTF receptor alpha (CNTF sR alpha) can be released from the cell surface by phosphatidylinositol-specific phospholipase C. CNTF sR alpha can be released from skeletal muscle in response to peripheral nerve injury and high concentrations of CNTF sR alpha have also been detected in human cerebrospinal fluid. CNTF sR alpha binds CNTF in solution and the complex can act on cells that express only LIF R beta and gp130 but not CNTF R alpha.