A new genetic model of activity-induced Ras signaling dependent pre-synaptic plasticity in Drosophila

Brain Res. 2010 Apr 22:1326:15-29. doi: 10.1016/j.brainres.2010.02.061. Epub 2010 Feb 26.

Abstract

Techniques to induce activity-dependent neuronal plasticity in vivo allow the underlying signaling pathways to be studied in their biological context. Here, we demonstrate activity-induced plasticity at neuromuscular synapses of Drosophila double mutant for comatose (an NSF mutant) and Kum (a SERCA mutant), and present an analysis of the underlying signaling pathways. comt; Kum (CK) double mutants exhibit increased locomotor activity under normal culture conditions, concomitant with a larger neuromuscular junction synapse and stably elevated evoked transmitter release. The observed enhancements of synaptic size and transmitter release in CK mutants are completely abrogated by: a) reduced activity of motor neurons; b) attenuation of the Ras/ERK signaling cascade; or c) inhibition of the transcription factors Fos and CREB. All of which restrict synaptic properties to near wild type levels. Together, these results document neural activity-dependent plasticity of motor synapses in CK animals that requires Ras/ERK signaling and normal transcriptional activity of Fos and CREB. Further, novel in vivo reporters of neuronal Ras activation and Fos transcription also confirm increased signaling through a Ras/AP-1 pathway in motor neurons of CK animals, consistent with results from our genetic experiments. Thus, this study: a) provides a robust system in which to study activity-induced synaptic plasticity in vivo; b) establishes a causal link between neural activity, Ras signaling, transcriptional regulation and pre-synaptic plasticity in glutamatergic motor neurons of Drosophila larvae; and c) presents novel, genetically encoded reporters for Ras and AP-1 dependent signaling pathways in Drosophila.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • CREB-Binding Protein / genetics
  • CREB-Binding Protein / metabolism
  • Coma / genetics
  • Drosophila / genetics
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Enzyme Activation / genetics
  • Gene Expression Regulation / genetics
  • Models, Animal*
  • Neuromuscular Junction / genetics*
  • Neuronal Plasticity / genetics*
  • Signal Transduction / genetics*
  • Transcription Factor AP-1 / genetics
  • Transcription Factor AP-1 / metabolism
  • ras Proteins / genetics*

Substances

  • Drosophila Proteins
  • Transcription Factor AP-1
  • kay protein, Drosophila
  • CREB-Binding Protein
  • ras Proteins