Structural requirements of the interleukin-6 signal transducer gp130 for its interaction with Janus kinase 1: the receptor is crucial for kinase activation

2001 ◽  
Vol 361 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Claude HAAN ◽  
Peter C. HEINRICH ◽  
Iris BEHRMANN
Keyword(s):  
Point Mutations ◽  
Proximal Region ◽  
Janus Kinase ◽  
Signal Transducer ◽  
Kinase Activation ◽  
Gp130 Receptor ◽  
Janus Kinase 1 ◽  
Receptor Chain ◽  
Common Signal ◽  
Membrane Proximal Region

We analysed the interaction of gp130, the common signal-transducing receptor chain of interleukin (IL)-6 type cytokines, with Jak1, the Janus family kinase which is crucial for signal transduction of this group of cytokines. With a truncated chimaeric IL-5Rβ–gp130 receptor expressed in COS-7 cells, we show that the membrane-proximal 69 amino acids are sufficient to mediate Jak1 binding and activation. Deletion of box2 drastically reduced binding of endogenous, but not of overexpressed, Jak1. Several point mutations in the membrane-proximal region of gp130 (W652A, P671/P672A, F676A, Y683F, where W, A, P, F and Y are tryptophan, alanine, proline, phenylalanine and tyrosine) did not affect Jak1 association. However, stimulation of chimaeric receptors with the mutations P671/P672A and F676A in the interbox1/box2 region resulted in a reduced activation of STAT (signal transducer and activator of transcription) transcription factors. Most importantly, signalling by the receptor with the box1 mutation W652A was totally abrogated. Although this mutation did not affect Jak1 association, stimulation-dependent phosphorylation of Jak1 was prevented. The W652 mutation acts dominantly, since no signalling occured even when only a single cytoplasmic chain of a gp130 dimer contained the mutation. Our data demonstrate that the mere proximity of Jaks in an activated receptor complex is not sufficient to mediate their activation. Rather, it seems that parts of the receptor, including the box1 region, are involved in positioning Jaks correctly so that ligand-induced receptor dimerization and reorientation can lead to their mutual activation and subsequently to downstream signalling events.

A single amino acid substitution (Trp666→Ala) in the interbox1/2 region of the interleukin-6 signal transducer gp130 abrogates binding of JAK1, and dominantly impairs signal transduction

2000 ◽  
Vol 349 (1) ◽  
pp. 261-266 ◽  
Author(s):  
Claude HAAN ◽  
Heike M. HERMANNS ◽  
Peter C. HEINRICH ◽  
Iris BEHRMANN
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Janus Kinase ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Signal Transducer ◽  
Receptor Chain ◽  
The Common ◽  
Common Signal ◽  
First Time

gp130 is the common signal-transducing receptor chain of interleukin (IL)-6-type cytokines. Here we describe, for the first time, a single amino acid substitution (Trp666 → Ala) in the membrane-proximal interbox1/2 region that abrogates activation of STAT (signal transducer and activator of transcription) transcription factors and the proliferative response of pro-B-cell transfectants. Moreover, association of the Janus kinase JAK1 is prevented. No signalling of heterodimeric IL-5 receptor (IL-5R)/gp130 chimaeras occurs in COS-7 cells, even when only a single cytoplasmic chain of a gp130 dimer contains the Trp666Ala mutation, indicating that it acts dominantly.

scholarly journals Immunohistochemical study of janus kinase 1/signal transducer and activator of transcription 3 in psoriasis vulgaris

2019 ◽  
Vol Volume 12 ◽  
pp. 497-508
Author(s):  
Azza Gaber Antar Farag ◽  
Rehab Samaka ◽  
Eman Nabil Elshafey ◽  
Wafaa Ahmed Shehata ◽  
Eman Gamal El Sherbiny ◽  
...  
Keyword(s):  
Psoriasis Vulgaris ◽  
Immunohistochemical Study ◽  
Janus Kinase ◽  
Signal Transducer ◽  
Janus Kinase 1 ◽  
Transcription 3

scholarly journals A membrane-proximal region of the interleukin-2 receptor gamma c chain sufficient for Jak kinase activation and induction of proliferation in T cells.

1996 ◽  
Vol 16 (1) ◽  
pp. 309-317 ◽  
Author(s):  
B H Nelson ◽  
J D Lord ◽  
P D Greenberg
Keyword(s):  
T Cells ◽  
Proliferative Response ◽  
Interleukin 2 ◽  
Receptor Activation ◽  
Proximal Region ◽  
Sh2 Domains ◽  
Receptor Chain ◽  
Mitogenic Signalling ◽  
Macrophage Colony ◽  
Membrane Proximal Region

The interleukin-2 (IL-2) receptor (IL-2R) consists of three distinct subunits (alpha, beta, and gamma c) and regulates proliferation of T lymphocytes. Intracellular signalling results from ligand-mediated heterodimerization of the cytoplasmic domains of the beta and gamma c chains. To identify the residues of gamma c critical to this process, mutations were introduced into the cytoplasmic domain, and the effects on signalling were analyzed in the IL-2-dependent T-cell line CTLL2 and T-helper clone D10, using chimeric IL-2R chains that bind and are activated by granulocyte-macrophage colony-stimulating factor. Whereas previous studies of fibroblasts and transformed T cells have suggested that signalling by gamma c requires both membrane-proximal and C-terminal subdomains, our results for IL-2-dependent T cells demonstrate that the membrane-proximal 52 amino acids are sufficient to mediate a normal proliferative response, including induction of the proto-oncogenes c-myc and c-fos. Although gamma c is phosphorylated on tyrosine upon receptor activation and could potentially interact with downstream molecules containing SH2 domains, cytoplasmic tyrosine residues were dispensable for mitogenic signalling. However, deletion of a membrane-proximal region conserved among other cytokine receptors (cytoplasmic residues 5 to 37) or an adjacent region unique to gamma c (residues 40 to 52) abrogated functional interaction of the receptor chain with the tyrosine kinase Jak3. This correlated with a loss of all signalling events analyzed, including phosphorylation of the IL-2R beta-associated kinase Jak1, expression of c-myc and c-fos, and induction of the proliferative response. Thus, it appears in T cells that Jak3 is a critical mediator of mitogenic signaling by the gamma c chain.

scholarly journals Characterization of the Rapid Proteolytic Shedding of Murine L-Selectin

2001 ◽  
Vol 8 (3-4) ◽  
pp. 267-277 ◽  
Author(s):  
Li-Chao Zhao ◽  
John B. Edgar ◽  
Morris O. Dailey
Keyword(s):  
Cleavage Site ◽  
Point Mutations ◽  
Proximal Region ◽  
Sequence Specificity ◽  
Site Analysis ◽  
Maximal Induction ◽  
A Site ◽  
Proteolytic Shedding ◽  
Membrane Proximal Region

The structural requirements for L-selectin shedding were studied in murine leukocytes. Upon activation, L-selectin on both lymphocytes and neutrophils undergoes cleavage by a membrane metalloprotease, resulting in the generation of a soluble ectodomain and a membrane- retained 6 kD fragment. Radiochemical sequencing demonstrated a cleavage site in the membrane-proximal region (MPR) between R321 and S322, which is homologous to the human site. Although intact neutrophil L-selectin is larger, it is cleaved at the same, or very close, site. Analysis of several transfectants expressing L-selectin point mutations and chimeric constructs suggest that, like human shedding, the proteolytic process has relatively loose sequence specificity for the substrate site. In addition, some constructs are susceptible to slow constitutive cleavage, but their shedding does not increase upon PMA stimulation, showing that basal and activated shedding are separable processes. Insertion of the 15 amino acid MPR into murine B7.2 conferred upon this molecule susceptibility to constitutive shedding. PMA stimulation results in little or no acceleration of down regulation of this molecule. These results suggest that recognition of both the membrane-proximal cleavage site and of a site distant from the MPR are required for maximal induction of L-selectin shedding.

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