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Cytokine-Like Factor 1, an Essential Facilitator of Cardiotrophin-Like Cytokine:Ciliary Neurotrophic Factor Receptor α Signaling and sorLA-Mediated Turnover.

Larsen JV, Kristensen AM, Pallesen LT, Bauer J, Vægter CB, Nielsen MS, Madsen P, Petersen CM - Mol. Cell. Biol. (2016)

Bottom Line: The site for CNTFRα enables CLF-1 to promote CLC:CNTFRα complex formation and signaling.The second site establishes a link between the endocytic receptor sorLA and the tripartite CLC:CLF-1:CNTFRα complex and allows sorLA to downregulate the CNTFRα pool in stimulated cells.Finally, sorLA may bind and concentrate the tripartite soluble CLC:CLF-1:CNTFRα complex on cell membranes and thus facilitate its signaling through gp130/LIFRβ.

View Article: PubMed Central - PubMed

Affiliation: The MIND Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark jvl@biomed.au.dk cmp@biomed.au.dk.

No MeSH data available.


Related in: MedlinePlus

sorLA's influence on CLC:CLF-1 signaling in cells with or without endogenous expression of CNTFRα. (A) CNTFRα-expressing HEK293 cells were stimulated (15 min) with 10 nM CLC:CLF-1 or with the fusion protein CLC-sCNTFRα as indicated. The columns show the response, in terms of pSTAT3, in wt HEK293 cells (−) and in sorLA transfectants. Data represent means ± SEMs (n = 3) relative to the pSTAT3 level in wt cells stimulated with CLC:CLF-1. (B) Levels of pSTAT3 in CNTFRα-deficient (but gp130/LIFRβ-positive) Ba/F3 cells upon stimulation with a combination of 10 nM CLC:CLF-1 and sCNTFRα or with the CLC-sCNTFRα fusion protein. Results in sorLA transfectants (means ± SEMs, n = 3) are shown relative to results obtained in wt cells (−).
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Figure 8: sorLA's influence on CLC:CLF-1 signaling in cells with or without endogenous expression of CNTFRα. (A) CNTFRα-expressing HEK293 cells were stimulated (15 min) with 10 nM CLC:CLF-1 or with the fusion protein CLC-sCNTFRα as indicated. The columns show the response, in terms of pSTAT3, in wt HEK293 cells (−) and in sorLA transfectants. Data represent means ± SEMs (n = 3) relative to the pSTAT3 level in wt cells stimulated with CLC:CLF-1. (B) Levels of pSTAT3 in CNTFRα-deficient (but gp130/LIFRβ-positive) Ba/F3 cells upon stimulation with a combination of 10 nM CLC:CLF-1 and sCNTFRα or with the CLC-sCNTFRα fusion protein. Results in sorLA transfectants (means ± SEMs, n = 3) are shown relative to results obtained in wt cells (−).

Mentions: To determine if sorLA impacts cellular signaling via its ability to interact with CLC:CLF-1 bound to CNTFRα, we first examined STAT3 phosphorylation in HEK293 cells with endogenous expression of CNTFRα. The cells were untransfected or transfected with sorLA and were stimulated for 15 min with either 5 nM CLC:CLF-1 or a 5 nM concentration of the fusion protein CLC-sCNTFRα. The pSTAT3 level was measured by Western blotting, and the results are shown (Fig. 8A) relative to the level obtained in untransfected HEK293 cells responding to CLC:CLF-1. As can be seen, expression of sorLA did not significantly alter the response. A similar experiment was next performed in CNTFRα-deficient Ba/F3 cells (expressing gp130/LIFRβ), but in this case stimulation with CLC:CLF-1 was performed in the presence of sCNTFRα (Fig. 8B). Again the responses to stimulation with the fusion protein, which does not bind sorLA, did not differ significantly between untransfected cells and sorLA transfectants. However, in cells subjected to CLC:CLF-1 and sCNTFRα, the resulting level of pSTAT3 was about 4-fold higher in the sorLA transfectants than in the untransfected Ba/F3 cells. Taken together, the two experiments strongly indicate that sorLA may serve to bind and concentrate circulating tripartite complexes of CLC:CLF-1 and sCNTFRα on the cell membrane and thereby promote their interaction with gp130/LIFRβ and signaling. This effect appears to be insignificant on cells that express CNTFRα but may have a significant effect on cells without endogenous expression of CNTFRα.


Cytokine-Like Factor 1, an Essential Facilitator of Cardiotrophin-Like Cytokine:Ciliary Neurotrophic Factor Receptor α Signaling and sorLA-Mediated Turnover.

Larsen JV, Kristensen AM, Pallesen LT, Bauer J, Vægter CB, Nielsen MS, Madsen P, Petersen CM - Mol. Cell. Biol. (2016)

sorLA's influence on CLC:CLF-1 signaling in cells with or without endogenous expression of CNTFRα. (A) CNTFRα-expressing HEK293 cells were stimulated (15 min) with 10 nM CLC:CLF-1 or with the fusion protein CLC-sCNTFRα as indicated. The columns show the response, in terms of pSTAT3, in wt HEK293 cells (−) and in sorLA transfectants. Data represent means ± SEMs (n = 3) relative to the pSTAT3 level in wt cells stimulated with CLC:CLF-1. (B) Levels of pSTAT3 in CNTFRα-deficient (but gp130/LIFRβ-positive) Ba/F3 cells upon stimulation with a combination of 10 nM CLC:CLF-1 and sCNTFRα or with the CLC-sCNTFRα fusion protein. Results in sorLA transfectants (means ± SEMs, n = 3) are shown relative to results obtained in wt cells (−).
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Related In: Results  -  Collection

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Figure 8: sorLA's influence on CLC:CLF-1 signaling in cells with or without endogenous expression of CNTFRα. (A) CNTFRα-expressing HEK293 cells were stimulated (15 min) with 10 nM CLC:CLF-1 or with the fusion protein CLC-sCNTFRα as indicated. The columns show the response, in terms of pSTAT3, in wt HEK293 cells (−) and in sorLA transfectants. Data represent means ± SEMs (n = 3) relative to the pSTAT3 level in wt cells stimulated with CLC:CLF-1. (B) Levels of pSTAT3 in CNTFRα-deficient (but gp130/LIFRβ-positive) Ba/F3 cells upon stimulation with a combination of 10 nM CLC:CLF-1 and sCNTFRα or with the CLC-sCNTFRα fusion protein. Results in sorLA transfectants (means ± SEMs, n = 3) are shown relative to results obtained in wt cells (−).
Mentions: To determine if sorLA impacts cellular signaling via its ability to interact with CLC:CLF-1 bound to CNTFRα, we first examined STAT3 phosphorylation in HEK293 cells with endogenous expression of CNTFRα. The cells were untransfected or transfected with sorLA and were stimulated for 15 min with either 5 nM CLC:CLF-1 or a 5 nM concentration of the fusion protein CLC-sCNTFRα. The pSTAT3 level was measured by Western blotting, and the results are shown (Fig. 8A) relative to the level obtained in untransfected HEK293 cells responding to CLC:CLF-1. As can be seen, expression of sorLA did not significantly alter the response. A similar experiment was next performed in CNTFRα-deficient Ba/F3 cells (expressing gp130/LIFRβ), but in this case stimulation with CLC:CLF-1 was performed in the presence of sCNTFRα (Fig. 8B). Again the responses to stimulation with the fusion protein, which does not bind sorLA, did not differ significantly between untransfected cells and sorLA transfectants. However, in cells subjected to CLC:CLF-1 and sCNTFRα, the resulting level of pSTAT3 was about 4-fold higher in the sorLA transfectants than in the untransfected Ba/F3 cells. Taken together, the two experiments strongly indicate that sorLA may serve to bind and concentrate circulating tripartite complexes of CLC:CLF-1 and sCNTFRα on the cell membrane and thereby promote their interaction with gp130/LIFRβ and signaling. This effect appears to be insignificant on cells that express CNTFRα but may have a significant effect on cells without endogenous expression of CNTFRα.

Bottom Line: The site for CNTFRα enables CLF-1 to promote CLC:CNTFRα complex formation and signaling.The second site establishes a link between the endocytic receptor sorLA and the tripartite CLC:CLF-1:CNTFRα complex and allows sorLA to downregulate the CNTFRα pool in stimulated cells.Finally, sorLA may bind and concentrate the tripartite soluble CLC:CLF-1:CNTFRα complex on cell membranes and thus facilitate its signaling through gp130/LIFRβ.

View Article: PubMed Central - PubMed

Affiliation: The MIND Center, Department of Biomedicine, Aarhus University, Aarhus, Denmark jvl@biomed.au.dk cmp@biomed.au.dk.

No MeSH data available.


Related in: MedlinePlus