Structure of the Sec23p/24p and Sec13p/31p complexes of COPII

Proc Natl Acad Sci U S A. 2001 Sep 11;98(19):10704-9. doi: 10.1073/pnas.191359398. Epub 2001 Sep 4.


COPII-coated vesicles carry proteins from the endoplasmic reticulum to the Golgi complex. This vesicular transport can be reconstituted by using three cytosolic components containing five proteins: the small GTPase Sar1p, the Sec23p/24p complex, and the Sec13p/Sec31p complex. We have used a combination of biochemistry and electron microscopy to investigate the molecular organization and structure of Sec23p/24p and Sec13p/31p complexes. The three-dimensional reconstruction of Sec23p/24p reveals that it has a bone-shaped structure, (17 nm in length), composed of two similar globular domains, one corresponding to Sec23p and the other to Sec24p. Sec13p/31p is a heterotetramer composed of two copies of Sec13p and two copies of Sec31p. It has an elongated shape, is 28-30 nm in length, and contains five consecutive globular domains linked by relatively flexible joints. Putting together the architecture of these Sec complexes with the interactions between their subunits and the appearance of the coat in COPII-coated vesicles, we present a model for COPII coat organization.

Publication types

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

MeSH terms

  • COP-Coated Vesicles / chemistry*
  • Carrier Proteins / chemistry*
  • Carrier Proteins / ultrastructure
  • Dimerization
  • Fungal Proteins / chemistry*
  • Fungal Proteins / ultrastructure
  • GTPase-Activating Proteins
  • Membrane Proteins / chemistry*
  • Membrane Proteins / ultrastructure
  • Models, Molecular
  • Nuclear Pore Complex Proteins
  • Phosphoproteins / chemistry*
  • Phosphoproteins / ultrastructure
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae Proteins*
  • Vesicular Transport Proteins


  • Carrier Proteins
  • Fungal Proteins
  • GTPase-Activating Proteins
  • Membrane Proteins
  • Nuclear Pore Complex Proteins
  • Phosphoproteins
  • SEC13 protein, S cerevisiae
  • SEC23 protein, S cerevisiae
  • SEC24 protein, S cerevisiae
  • SEC31 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Vesicular Transport Proteins