Stahl N, Davis S, Wong V, Taga T, Kishimoto T, Ip N Y, Yancopoulos G D
Institute for Molecular and Cellular Biology, Osaka University, Japan.
J Biol Chem. 1993 Apr 15;268(11):7628-31.
Ciliary neurotrophic factor (CNTF) and leukemia inhibitory factor (LIF) are cytokines that give rise to an identical set of tyrosine-phosphorylated proteins upon addition to responsive cells. One of these proteins is the interleukin-6 signal-transducing molecule gp130, which is required for signal transduction by both CNTF and LIF. Here we identify another prominent tyrosine-phosphorylated protein as LIF receptor (LIFR) beta, which was originally cloned as a LIF-binding protein. Cross-linking experiments with iodinated factors were carried out on a cell line responsive to CNTF and LIF, as well as on COS cells that were cotransfected with various combinations of gp130, LIFR beta, and CNTF receptor (CNTFR) alpha, the previously cloned CNTF-binding protein. These experiments reveal that LIF cross-links to LIFR beta alone, as well as to gp130 when it is coexpressed with LIFR beta. However, cross-linking of CNTF to LIFR beta and gp130 is only observed in the presence of CNTFR alpha. These and other data show that the two known LIF receptor components are recruited by CNTF and CNTFR alpha to form a trimeric CNTF receptor complex.
睫状神经营养因子（CNTF）和白血病抑制因子（LIF）是细胞因子，当添加到反应性细胞中时，它们会产生一组相同的酪氨酸磷酸化蛋白。其中一种蛋白是白细胞介素-6信号转导分子gp130，它是CNTF和LIF信号转导所必需的。在这里，我们确定另一种显著的酪氨酸磷酸化蛋白为LIF受体（LIFR）β，它最初被克隆为一种LIF结合蛋白。我们用碘化因子对一种对CNTF和LIF有反应的细胞系，以及用gp130、LIFRβ和CNTF受体（CNTFR）α（先前克隆的CNTF结合蛋白）的各种组合共转染的COS细胞进行了交联实验。这些实验表明，LIF单独与LIFRβ交联，当它与LIFRβ共表达时也与gp130交联。然而，只有在存在CNTFRα的情况下才能观察到CNTF与LIFRβ和gp130的交联。这些以及其他数据表明，两种已知的LIF受体成分被CNTF和CNTFRα募集，形成三聚体CNTF受体复合物。
