title: The Cdk5/p35 kinases modulate leptin-induced STAT3 signaling.
abstract: Cyclin-dependent kinase (Cdk) 5 is ubiquitously expressed in the brain and plays an essential role in central nervous system development and synaptic plasticity. The p35 kinase is a neuronal specific activator of Cdk5. Here, we show for the first time that Cdk5 activation modulates leptin signaling. P35 and its metabolite p25 were colocalized with the leptin receptor ObR in selective neurons in the hypothalamus. Overexpression of p35 alone was sufficient to induce the transcriptional activation of signal transducer and activator of transcription 3 (STAT3) in a cellular model. In retinoic acid-differentiated SH-SY5Y neuronal cells where ObRb was induced, leptin increased the expression of Cdk5, p35, and p25 kinases. The time course of induction coincided with that of phosphorylated (p)-STAT3. When Cdk5 activity was inhibited, either by roscovitine or overexpression of dominant negative Cdk5, there was a reduction of pSTAT3 activation. The results show that the activation of Cdk5 by p35 sustained leptin-induced pSTAT3 at 3-6 h. Thus, p35 is a novel modulator of leptin-induced STAT3 signaling.
authors.affiliation: Blood-Brain Barrier Group, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: He
authors.forename: Abba J
authors.initials: AJ
authors.lastname: Kastin
authors.forename: Hung
authors.initials: H
authors.lastname: Hsuchou
authors.forename: Weihong
authors.initials: W
authors.lastname: Pan
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D051360:Cyclin-Dependent Kinase 5 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism*; D011687:Purines / Q000378:metabolism; D011897:Random Allocation; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism; D000077546:Roscovitine; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: C492236:Cdk5r1 protein, mouse; D020738:Leptin; D011687:Purines; D054411:Receptors, Leptin; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse; C515447:leptin receptor, mouse; D000077546:Roscovitine; D010770:Phosphotransferases; D051360:Cyclin-Dependent Kinase 5