Real-time detection reveals that effectors couple dynamin's GTP-dependent conformational changes to the membrane

Rajesh Ramachandran, Sandra L. Schmid

Research output: Contribution to journalArticle

82 Scopus citations

Abstract

The GTPase dynamin is a mechanochemical enzyme involved in membrane fission, but the molecular nature of its membrane interactions and their regulation by guanine nucleotides and protein effectors remain poorly characterized. Using site-directed fluorescence labeling and several independent fluorescence spectroscopic techniques, we have developed robust assays for the detection and real-time monitoring of dynamin-membrane and dynamin-dynamin interactions. We show that dynamin interacts preferentially with highly curved, PIP2-dense membranes and inserts partially into the lipid bilayer. Our kinetic measurements further reveal that cycles of GTP binding and hydrolysis elicit major conformational rearrangements in self-assembled dynamin that favor dynamin-membrane association and dissociation, respectively. Sorting nexin 9, an abundant dynamin partner, transiently stabilizes dynamin on the membrane at the onset of stimulated GTP hydrolysis and may function to couple dynamin's mechanochemical conformational changes to membrane destabilization. Amphiphysin I has the opposite effect. Thus, dynamin's mechanochemical properties on a membrane surface are dynamically regulated by its GTPase cycle and major binding partners.

Original languageEnglish (US)
Pages (from-to)27-37
Number of pages11
JournalEMBO Journal
Volume27
Issue number1
DOIs
StatePublished - Jan 9 2008

Keywords

  • Conformational changes
  • Dynamin
  • Effectors
  • Fluorescence spectroscopy
  • Membrane fission

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

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