Enhancement of dynamin polymerization and GTPase activity by Arc/Arg3.1

Christopher E. Byers, Barbara Barylko, Justin A. Ross, Daniel R. Southworth, Nicholas G. James, Clinton A. Taylor, Lei Wang, Katie A. Collins, Armando Estrada, Maggie Waung, Tara C. Tassin, Kimberly M. Huber, David M. Jameson, Joseph P. Albanesi

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

Background The Activity-regulated cytoskeleton-associated protein, Arc, is an immediate-early gene product implicated in various forms of synaptic plasticity. Arc promotes endocytosis of AMPA type glutamate receptors and regulates cytoskeletal assembly in neuronal dendrites. Its role in endocytosis may be mediated by its reported interaction with dynamin 2, a 100 kDa GTPase that polymerizes around the necks of budding vesicles and catalyzes membrane scission. Methods Enzymatic and turbidity assays are used in this study to monitor effects of Arc on dynamin activity and polymerization. Arc oligomerization is measured using a combination of approaches, including size exclusion chromatography, sedimentation analysis, dynamic light scattering, fluorescence correlation spectroscopy, and electron microscopy. Results We present evidence that bacterially-expressed His6-Arc facilitates the polymerization of dynamin 2 and stimulates its GTPase activity under physiologic conditions (37 °C and 100 mM NaCl). At lower ionic strength Arc also stabilizes pre-formed dynamin 2 polymers against GTP-dependent disassembly, thereby prolonging assembly-dependent GTP hydrolysis catalyzed by dynamin 2. Arc also increases the GTPase activity of dynamin 3, an isoform of implicated in dendrite remodeling, but does not affect the activity of dynamin 1, a neuron-specific isoform involved in synaptic vesicle recycling. We further show in this study that Arc (either His6-tagged or untagged) has a tendency to form large soluble oligomers, which may function as a scaffold for dynamin assembly and activation. Conclusions and general significance The ability of Arc to enhance dynamin polymerization and GTPase activation may provide a mechanism to explain Arc-mediated endocytosis of AMPA receptors and the accompanying effects on synaptic plasticity.

Original languageEnglish (US)
Pages (from-to)1310-1318
Number of pages9
JournalBiochimica et Biophysica Acta - General Subjects
Volume1850
Issue number6
DOIs
StatePublished - Jun 1 2015

Keywords

  • Arc/Arg3.1
  • Dynamin
  • GTPase
  • Self-assembly

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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