title: The MAPK/ERK cascade targets both Elk-1 and cAMP response element-binding protein to control long-term potentiation-dependent gene expression in the dentate gyrus in vivo.
abstract: The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling cascade contributes to synaptic plasticity and to long-term memory formation, yet whether MAPK/ERK controls activity-dependent gene expression critical for long-lasting changes at the synapse and what the events underlying transduction of the signal are remain uncertain. Here we show that induction of long-term potentiation (LTP) in the dentate gyrus in vivo leads to rapid phosphorylation and nuclear translocation of MAPK/ERK. Following a similar time course, the two downstream transcriptional targets of MAPK/ERK, cAMP response element-binding protein (CREB) and the ternary complex factor Elk-1, a key transcriptional-regulator of serum response element (SRE)-driven gene expression, were hyperphosphorylated and the immediate early gene zif268 was upregulated. The mRNA encoding MAP kinase phosphatase MKP-1 was upregulated at the time point when MAPK/ERK phosphorylation had returned to basal levels, suggesting a negative feedback loop to regulate deactivation of MAPK/ERK. We also show that inhibition of the MAPK/ERK cascade by the MAPK kinase MEK inhibitor SL327 prevented CREB and Elk-1 phosphorylation, and LTP-dependent gene induction, resulting in rapidly decaying LTP. In conclusion, we suggest that Elk-1 forms an important link in the MAP kinase pathway to transduce signals from the cell surface to the nucleus to activate the genetic machinery necessary for the maintenance of synaptic plasticity in the dentate gyrus. Thus, MAPK/ERK activation is required for LTP-dependent transcriptional regulation and we suggest this is regulated by two parallel signaling pathways, the MAPK/ERK-Elk-1 pathway targeting SRE and the MAPK/ERK-CREB pathway targeting CRE.
authors.affiliation: Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire, et de la Communication, Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche (UMR) 8620, Université Paris Sud, 91405 Orsay, France.
authors.forename: S
authors.initials: S
authors.lastname: Davis
authors.forename: P
authors.initials: P
authors.lastname: Vanhoutte
authors.forename: C
authors.initials: C
authors.lastname: Pages
authors.forename: J
authors.initials: J
authors.lastname: Caboche
authors.forename: S
authors.initials: S
authors.lastname: Laroche
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics*; D018891:Dentate Gyrus / Q000378:metabolism / Q000502:physiology*; D054638:Dual Specificity Phosphatase 1; D051766:Early Growth Response Protein 1; D004558:Electric Stimulation; D007839:Functional Laterality; D005786:Gene Expression Regulation; D017874:Immediate-Early Proteins / Q000235:genetics*; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D050807:ets-Domain Protein Elk-1
chemical_list: D018797:Cell Cycle Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; C494114:Elk1 protein, rat; D017874:Immediate-Early Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D020928:Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517021:Dusp1 protein, rat; D017027:Protein Tyrosine Phosphatases