title: TORC1 regulates activity-dependent CREB-target gene transcription and dendritic growth of developing cortical neurons.
abstract: CREB-target gene transcription during neuronal excitation is important for many aspects of neuronal development and function, including dendrite morphogenesis. However, the signaling events that regulate cAMP response element-binding protein (CREB)-mediated gene transcription during dendritic development are not well understood. Herein we report that the CREB coactivator TORC1 (transducer of regulated CREB 1) is required for activity-dependent CREB-target gene expression and dendrite growth in developing cortical neurons. Ca(2+) influx via voltage-gated calcium channels induced TORC1 dephosphorylation and translocation into the nucleus in a calcineurin-dependent manner. Nuclear accumulation of TORC1 initiated the expression of CREB-target genes, including salt-inducible kinase 1 (SIK1). In response of persistent depolarization, de novo SIK1 protein in turn promoted TORC1 phosphorylation and consequent depletion of nucleus-localized TORC1. SIK1 induction thus appears to act as a negative feedback signal that prevents persistent CREB/TORC1-dependent transcription in the face of long-lasting neuronal activity. Overexpressing wild type TORC1 promoted basal as well as activity-induced dendritic growth, whereas expressing a dominant-negative form of TORC1 or downregulating TORC1 inhibited activity-dependent dendritic growth in vitro and in vivo. Together, these results suggest that neuronal activity-dependent dendritic growth in developing cortical neurons relies on transient TORC1-mediated CREB-target gene transcription.
authors.affiliation: Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Li
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takemori
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Zhi-Qi
authors.initials: ZQ
authors.lastname: Xiong
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D000831:Animals, Newborn; D050882:CREB-Binding Protein / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology / Q000254:growth & development; D003513:Cycloheximide / Q000494:pharmacology; D003712:Dendrites / Q000502:physiology*; D004622:Embryo, Mammalian; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D011189:Potassium Chloride / Q000494:pharmacology; D011247:Pregnancy; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D014162:Transfection / Q000379:methods
chemical_list: C519510:Crtc1 protein, rat; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D011189:Potassium Chloride; D003513:Cycloheximide; D050882:CREB-Binding Protein; D017346:Protein Serine-Threonine Kinases; C120299:Sik1 protein, rat