![]() ![]() ; ; et al in FEBS Letters (2001), 505(1), 87-91 The terminal portion of the Janus kinases (Jaks) contains a divergent FERM (Four-point-one, Ezrin, Radixin, Moesin) homology domain comprising 19 conserved hydrophobic regions. To determine the role of ... [more ▼] The terminal portion of the Janus kinases (Jaks) contains a divergent FERM (Four-point-one, Ezrin, Radixin, Moesin) homology domain comprising 19 conserved hydrophobic regions. To determine the role of this domain in governing recruitment of Jak1, but not Jak3, to the gp130 subunit of the interleukin-6 family of cytokine receptors, the interaction of three Jak1/Jak3 chimeras with gp130 was investigated. Chimeras 1, 2 and 3 (Jak1 FERM regions 1-19, 1-18 and 1-8/Jak3, respectively) were all enzymically active. Chimeras 1 and 2 interacted with the cytoplasmic domain of gp130, although less efficiently than Jak1. Only chimera 2, however, restored gp130 signalling in Jak1-negative cells. The data are consistent with recruitment of Jak1 to gp130 through the Jak1 FERM domain, but also emphasise the likely requirement for precise Jak/receptor orientation to sustain function. [less ▲] Detailed reference viewed: 148 (0 UL)![]() ![]() ; ; et al in EMBO Journal (2001), 20(19), 5431-42 A tripartite receptor comprising the external region of the erythropoietin (Epo) receptor, the transmembrane and JAK-binding domains of the gp130 subunit of the interleukin-6 (IL-6) receptor, and a seven ... [more ▼] A tripartite receptor comprising the external region of the erythropoietin (Epo) receptor, the transmembrane and JAK-binding domains of the gp130 subunit of the interleukin-6 (IL-6) receptor, and a seven amino acid STAT1 recruitment motif (Y440) from the interferon (IFN)-gamma receptor, efficiently mediates an IFN-gamma-like response. An analogous completely foreign chimeric receptor in which the Y440 motif is replaced with the Y905 motif from gp130 also mediates an IFN-gamma-like response, but less efficiently. The IFNGR1 signal-transducing subunit of the IFN-gamma receptor is tyrosine phosphorylated through the chimeric receptors and the endogenous IL-6 and OSM receptors. Cross phosphorylation of IFNGR1 is not, however, required for the IFN-gamma-like response through the chimeric receptors, nor does it mediate an IFN-gamma-like response to IL-6 or OSM. The data argue strongly for modular JAK/STAT signalling and against any rigid structural organization for the "pathways" involved. They emphasize the likely high degree of overlap between the signals generated from disparate JAK-receptor complexes and show that relatively minor changes in such complexes can profoundly affect the response. [less ▲] Detailed reference viewed: 158 (0 UL) |
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