title: Roles of extracellular signal-regulated kinase and Akt signaling in coordinating nuclear transcription factor-kappaB-dependent cell survival after serotonin 1A receptor activation.
abstract: To investigate the functional consequences of cross-talk between multiple effectors of serotonin (5-HT) 1A receptor, we employed transfected Chinese hamster ovary cells. Activation of 5-HT 1A receptor stimulated extracellular signal-regulated kinase (ERK)1/2, Akt and nuclear transcription factor-kappaB (NF-kappaB). Stimulation of cells with 5-HT 1A receptor agonist induced a rapid but transient ERK1/2 phosphorylation followed by increased phosphorylation of Akt. Elevated Akt activity in turn suppressed Raf activity and induced a decline in ERK activation. The activation of ERK and Akt downstream of 5-HT 1A receptor was sensitive to inhibitors of Ras, Raf and phosphatidylinositol 3-kinase (PI3K). Stimulation of 5-HT 1A receptor also resulted in activation of NF-kappaB through a decrease in inhibitor of nuclear transcription factor-kappaB. In support of the importance of 5-HT 1A receptor signaling for cell survival, inhibition of NF-kappaB facilitated caspase 3 activation and cleavage of poly (ADP-ribose) polymerase, while treatment of cells with agonist inhibited caspase 3, DNA fragmentation and cell death. Both agonist-dependent NF-kappaB activation and cell survival were decreased by Akt Inhibitor II or by overexpression of dominant-negative Akt. These findings suggest a role for 5-HT 1A receptor signaling in the Ras/Raf-dependent regulation of multiple intracellular signaling pathways that include ERK and PI3K/Akt. Of these, only PI3K/Akt and NF-kappaB activation were required for 5-HT 1A receptor-dependent cell survival, implying that the relative distribution of signals between competing transduction pathways determines the functional outcome of 5-HT 1A receptor activation.
authors.affiliation: Division of Neuroscience, New York State Psychiatric Institute, New York, New York 10032, USA.
authors.forename: Shu-chi
authors.initials: SC
authors.lastname: Hsiung
authors.forename: Hadassah
authors.initials: H
authors.lastname: Tamir
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Franke
authors.forename: Kuo-peing
authors.initials: KP
authors.lastname: Liu
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D005822:Genetic Vectors; D006801:Humans; D016328:NF-kappa B / Q000502:physiology*; D037342:Pertussis Toxin / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D010879:Piperazines / Q000494:pharmacology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D044282:Receptor, Serotonin, 5-HT1A / Q000187:drug effects*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D015398:Signal Transduction / Q000502:physiology*; D014343:Trypan Blue
chemical_list: D016328:NF-kappa B; D010879:Piperazines; D011725:Pyridines; D017366:Serotonin Receptor Agonists; D044282:Receptor, Serotonin, 5-HT1A; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D011065:Poly(ADP-ribose) Polymerases; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D014343:Trypan Blue