Neuropoietin activates STAT3 independent of LIFR activation in adipocytes.
Neuropoietin (NP) is a member of the gp130 cytokine family that is closely related to cardiotrophin-1(CT-1) and shares functional and structural features with other family members, including ciliary neurotrophic factor (CNTF) and cardiotrophin-like cytokine (CLC). Studies have shown that NP can play a role in the development of the nervous system, as well as affect adipogenesis and fat cell function. However, the signaling mechanisms utilized by NP in adipocytes have not been examined. In our present studies, we demonstrate that NP-induced activation of STAT3 tyrosine phosphorylation is independent of leukemia inhibitory factor receptor (LIFR) phosphorylation and degradation. Although it is widely accepted that NP signals via the LIFR, our studies reveal that NP results in phosphorylation of gp130, but not LIFR. These observations suggest that the profound effects that NP has on adipocytes are not mediated via LIFR signaling.
White
Ursula A
UA
Louisiana State University, Department of Biological Sciences, 202 Life Sciences Bldg., Baton Rouge, LA 70803, USA.
Stephens
Jacqueline M
JM
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D050822:Cytokine Receptor gp130 / Q000378:metabolism; D015850:Interleukin-6 / Q000494:pharmacology / Q000502:physiology*; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit / Q000378:metabolism*; D051379:Mice; D053681:Oncostatin M Receptor beta Subunit / Q000378:metabolism; D010766:Phosphorylation; D050796:STAT3 Transcription Factor / Q000378:metabolism*
D015850:Interleukin-6; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; C507841:Lifr protein, mouse; D053681:Oncostatin M Receptor beta Subunit; C508349:Osmr protein, mouse; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C486482:neuropoietin, mouse; D050822:Cytokine Receptor gp130