Crystal structure of human GGA1 GAT domain complexed with the GAT-binding domain of Rabaptin5

EMBO J. 2004 Oct 13;23(20):3909-17. doi: 10.1038/sj.emboj.7600411. Epub 2004 Sep 30.

Abstract

GGA proteins coordinate the intracellular trafficking of clathrin-coated vesicles through their interaction with several other proteins. The GAT domain of GGA proteins interacts with ARF, ubiquitin, and Rabaptin5. The GGA-Rabaptin5 interaction is believed to function in the fusion of trans-Golgi-derived vesicles to endosomes. We determined the crystal structure of a human GGA1 GAT domain fragment in complex with the Rabaptin5 GAT-binding domain. In this structure, the Rabaptin5 domain is a 90-residue-long helix. At the N-terminal end, it forms a parallel coiled-coil homodimer, which binds one GAT domain of GGA1. In the C-terminal region, it further assembles into a four-helix bundle tetramer. The Rabaptin5-binding motif of the GGA1 GAT domain consists of a three-helix bundle. Thus, the binding between Rabaptin5 and GGA1 GAT domain is based on a helix bundle-helix bundle interaction. The current structural observation is consistent with previously reported mutagenesis data, and its biological relevance is further confirmed by new mutagenesis studies and affinity analysis. The four-helix bundle structure of Rabaptin5 suggests a functional role in tethering organelles.

Publication types

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

MeSH terms

  • ADP-Ribosylation Factors / chemistry*
  • ADP-Ribosylation Factors / metabolism*
  • Adaptor Proteins, Vesicular Transport / chemistry*
  • Adaptor Proteins, Vesicular Transport / metabolism*
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Binding Sites
  • Crystallography, X-Ray*
  • Dimerization
  • Escherichia coli / genetics
  • Helix-Loop-Helix Motifs
  • Humans
  • Hydrophobic and Hydrophilic Interactions
  • Isoelectric Point
  • Models, Molecular
  • Molecular Sequence Data
  • Peptides / chemistry*
  • Polymers
  • Protein Binding
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Protein Transport
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Spectrum Analysis, Raman
  • Vesicular Transport Proteins / chemistry*
  • rab5 GTP-Binding Proteins / chemistry*
  • rab5 GTP-Binding Proteins / metabolism*

Substances

  • Adaptor Proteins, Vesicular Transport
  • GGA adaptor proteins
  • Peptides
  • Polymers
  • Recombinant Proteins
  • Vesicular Transport Proteins
  • GAT
  • ADP-Ribosylation Factors
  • rab5 GTP-Binding Proteins