Abstract
Leptin is an adipocyte-derived hormone that communicates the status of body energy stores to the brain to regulate feeding and energy balance. The inability of elevated leptin levels to adequately suppress feeding in obesity suggests attenuation of leptin action under these conditions; the activation of feedback circuits due to high leptin levels could contribute to this leptin resistance. Using cultured cells exogenously expressing the long form of the leptin receptor (LRb) or an erythropoietin receptor/LRb chimera, we show that chronic stimulation results in the attenuation of LRb signaling and the establishment of a state in which the receptor is refractory to reactivation. Mutation of LRb Tyr1138 (the site that recruits signal transducer and activator of transcription 3) alleviated this feedback inhibition, suggesting that signal transducer and activator of transcription 3 mediates the induction of a feedback inhibitor, such as suppressor of cytokine signaling 3 (SOCS3), during chronic LRb stimulation. Indeed, manipulation of the expression or activity of the LRb-binding tyrosine phosphatase, SH2-domaln containing phosphatase-2, by overexpression of wild-type and dominant negative isoforms or RNA interference-mediated knockdown did not alter the attenuation of LRb signals. In contrast, SOCS3 overexpression repressed LRb signaling, whereas RNA interference-mediated knockdown of SOCS3 resulted in increased LRb signaling that was not attenuated during chronic ligand stimulation. These data suggest that Tyr1138 of LRb and SOCS3 represent major effector pathways for the feedback inhibition of LRb signaling. Furthermore, we show that mice expressing an LRb isoform mutant for Tyr1138 display increased activity of the leptin-dependenf growth and immune axes, sugesting that Tyr 1138-mediated feedback inhibition may regulate leptin sensitivity in vivo.
| Original language | English |
|---|---|
| Pages (from-to) | 925-938 |
| Number of pages | 14 |
| Journal | Molecular Endocrinology |
| Volume | 19 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 1 2005 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Molecular Biology
- Endocrinology, Diabetes and Metabolism
Cite this
Feedback inhibition of leptin receptor/Jak2 signaling via Tyr 1138 of the leptin receptor and suppressor of cytokine signaling 3. / Dunn, Sarah L.; Björnholm, Marie; Bates, Sarah H.; Chen, Zhibin; Seifert, Matthew; Myers, Martin G.
In: Molecular Endocrinology, Vol. 19, No. 4, 01.04.2005, p. 925-938.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Feedback inhibition of leptin receptor/Jak2 signaling via Tyr 1138 of the leptin receptor and suppressor of cytokine signaling 3
AU - Dunn, Sarah L.
AU - Björnholm, Marie
AU - Bates, Sarah H.
AU - Chen, Zhibin
AU - Seifert, Matthew
AU - Myers, Martin G.
PY - 2005/4/1
Y1 - 2005/4/1
N2 - Leptin is an adipocyte-derived hormone that communicates the status of body energy stores to the brain to regulate feeding and energy balance. The inability of elevated leptin levels to adequately suppress feeding in obesity suggests attenuation of leptin action under these conditions; the activation of feedback circuits due to high leptin levels could contribute to this leptin resistance. Using cultured cells exogenously expressing the long form of the leptin receptor (LRb) or an erythropoietin receptor/LRb chimera, we show that chronic stimulation results in the attenuation of LRb signaling and the establishment of a state in which the receptor is refractory to reactivation. Mutation of LRb Tyr1138 (the site that recruits signal transducer and activator of transcription 3) alleviated this feedback inhibition, suggesting that signal transducer and activator of transcription 3 mediates the induction of a feedback inhibitor, such as suppressor of cytokine signaling 3 (SOCS3), during chronic LRb stimulation. Indeed, manipulation of the expression or activity of the LRb-binding tyrosine phosphatase, SH2-domaln containing phosphatase-2, by overexpression of wild-type and dominant negative isoforms or RNA interference-mediated knockdown did not alter the attenuation of LRb signals. In contrast, SOCS3 overexpression repressed LRb signaling, whereas RNA interference-mediated knockdown of SOCS3 resulted in increased LRb signaling that was not attenuated during chronic ligand stimulation. These data suggest that Tyr1138 of LRb and SOCS3 represent major effector pathways for the feedback inhibition of LRb signaling. Furthermore, we show that mice expressing an LRb isoform mutant for Tyr1138 display increased activity of the leptin-dependenf growth and immune axes, sugesting that Tyr 1138-mediated feedback inhibition may regulate leptin sensitivity in vivo.
AB - Leptin is an adipocyte-derived hormone that communicates the status of body energy stores to the brain to regulate feeding and energy balance. The inability of elevated leptin levels to adequately suppress feeding in obesity suggests attenuation of leptin action under these conditions; the activation of feedback circuits due to high leptin levels could contribute to this leptin resistance. Using cultured cells exogenously expressing the long form of the leptin receptor (LRb) or an erythropoietin receptor/LRb chimera, we show that chronic stimulation results in the attenuation of LRb signaling and the establishment of a state in which the receptor is refractory to reactivation. Mutation of LRb Tyr1138 (the site that recruits signal transducer and activator of transcription 3) alleviated this feedback inhibition, suggesting that signal transducer and activator of transcription 3 mediates the induction of a feedback inhibitor, such as suppressor of cytokine signaling 3 (SOCS3), during chronic LRb stimulation. Indeed, manipulation of the expression or activity of the LRb-binding tyrosine phosphatase, SH2-domaln containing phosphatase-2, by overexpression of wild-type and dominant negative isoforms or RNA interference-mediated knockdown did not alter the attenuation of LRb signals. In contrast, SOCS3 overexpression repressed LRb signaling, whereas RNA interference-mediated knockdown of SOCS3 resulted in increased LRb signaling that was not attenuated during chronic ligand stimulation. These data suggest that Tyr1138 of LRb and SOCS3 represent major effector pathways for the feedback inhibition of LRb signaling. Furthermore, we show that mice expressing an LRb isoform mutant for Tyr1138 display increased activity of the leptin-dependenf growth and immune axes, sugesting that Tyr 1138-mediated feedback inhibition may regulate leptin sensitivity in vivo.
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UR - http://www.scopus.com/inward/citedby.url?scp=15444366416&partnerID=8YFLogxK
U2 - 10.1210/me.2004-0353
DO - 10.1210/me.2004-0353
M3 - Article
C2 - 15604114
AN - SCOPUS:15444366416
VL - 19
SP - 925
EP - 938
JO - Molecular Endocrinology
JF - Molecular Endocrinology
SN - 0888-8809
IS - 4
ER -