title: Regulation of cortical dendrite development by Rap1 signaling.
abstract: Rap1 is a small GTP-binding protein that has been implicated in intracellular signaling and cytoskeletal control. Here, we show that Rap1 is expressed in rat cortical neurons and plays a critical role in dendritic development. Inhibition of Rap1 signaling either by expressing dominant negative mutant of Rap1 or Rap1GAP in cortical neurons reduced dendritic complexity. In contrast, expression of a constitutively active mutant of Rap1 (Rap1V12) induced dendritic growth and branching. Membrane depolarization, which induces dendritic growth via calcium influx, led to a rapid activation of Rap1 via cAMP and cGMP signaling. A CREB-dependent mechanism is involved in depolarization-induced dendritic growth in cortical neurons. Rap1 function contributed to depolarization induced CREB activation, and inhibition of CREB suppressed dendritic growth induced by Rap1V12. These observations identify Rap1 as a key mediator of calcium regulation of CREB-dependent transcription and dendritic development.
authors.affiliation: Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Yachi
authors.initials: Y
authors.lastname: Chen
authors.forename: Phyllis Y
authors.initials: PY
authors.lastname: Wang
authors.forename: Anirvan
authors.initials: A
authors.lastname: Ghosh
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D015220:Calcium Channels / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000196:embryology* / Q000254:growth & development*; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D008564:Membrane Potentials / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D051381:Rats; D020318:Rats, Long-Evans; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics; D020827:rap1 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; D017362:Cyclic AMP Response Element-Binding Protein; D016194:Receptors, N-Methyl-D-Aspartate; D000242:Cyclic AMP; D048052:Mitogen-Activated Protein Kinase 3; D020827:rap1 GTP-Binding Proteins; D006152:Cyclic GMP