Sec15 interacts with Rab11 via a novel domain and affects Rab11 localization in vivo

Nat Struct Mol Biol. 2005 Oct;12(10):879-85. doi: 10.1038/nsmb987. Epub 2005 Sep 11.


Sec15, a component of the exocyst, recognizes vesicle-associated Rab GTPases, helps target transport vesicles to the budding sites in yeast and is thought to recruit other exocyst proteins. Here we report the characterization of a 35-kDa fragment that comprises most of the C-terminal half of Drosophila melanogaster Sec15. This C-terminal domain was found to bind a subset of Rab GTPases, especially Rab11, in a GTP-dependent manner. We also provide evidence that in fly photoreceptors Sec15 colocalizes with Rab11 and that loss of Sec15 affects rhabdomere morphology. Determination of the 2.5-A crystal structure of the C-terminal domain revealed a novel fold consisting of ten alpha-helices equally distributed between two subdomains (N and C subdomains). We show that the C subdomain, mainly via a single helix, is sufficient for Rab binding.

Publication types

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

MeSH terms

  • Animals
  • Crystallography
  • Drosophila / metabolism*
  • Drosophila Proteins / chemistry*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Photoreceptor Cells, Invertebrate / chemistry*
  • Photoreceptor Cells, Invertebrate / metabolism
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Vesicular Transport Proteins / chemistry*
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • rab GTP-Binding Proteins / analysis*
  • rab GTP-Binding Proteins / metabolism


  • Drosophila Proteins
  • Sec15 protein, Drosophila
  • Vesicular Transport Proteins
  • rab11 protein
  • rab GTP-Binding Proteins

Associated data

  • PDB/2A2F