Dynamics of the COPII coat with GTP and stable analogues

Nat Cell Biol. 2001 Jun;3(6):531-7. doi: 10.1038/35078500.


We have developed an assay to monitor the assembly of the COPII coat onto liposomes in real time. We show that with Sar1pGTP bound to liposomes, a single round of assembly and disassembly of the COPII coat lasts a few seconds. The two large COPII complexes Sec23/24p and Sec13/31p bind almost instantaneously (in less than 1 s) to Sar1pGTP-doped liposomes. This binding is followed by a fast (less than 10 s) disassembly due to a 10-fold acceleration of the GTPase-activating protein activity of Sec23/24p by the Sec13/31p complex. Experiments with the phosphate analogue BeFx suggest that Sec23/24p provides residues directly involved in GTP hydrolysis on Sar1p.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • COP-Coated Vesicles / metabolism*
  • Fungal Proteins / metabolism
  • GTPase-Activating Proteins
  • Guanosine Triphosphate / metabolism*
  • Liposomes / metabolism
  • Monomeric GTP-Binding Proteins / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Temperature
  • Vesicular Transport Proteins


  • Fungal Proteins
  • GTPase-Activating Proteins
  • Liposomes
  • SEC23 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Vesicular Transport Proteins
  • Guanosine Triphosphate
  • Monomeric GTP-Binding Proteins
  • SAR1 protein, S cerevisiae