The structures of exocyst subunit Exo70p and the Exo84p C-terminal domains reveal a common motif.
The exocyst is a large complex that is required for tethering vesicles at the final stages of the exocytic pathway in all eukaryotes. Here we present the structures of the Exo70p subunit of this complex and of the C-terminal domains of Exo84p, at 2.0-A and 2.85-A resolution, respectively. Exo70p forms a 160-A-long rod with a novel fold composed of contiguous alpha-helical bundles. The Exo84p C terminus also forms a long rod (80 A), which unexpectedly has the same fold as the Exo70p N terminus. Our structural results and our experimental observations concerning the interaction between Exo70p and other exocyst subunits or Rho3p GTPase are consistent with an architecture wherein exocyst subunits are composed of mostly helical modules strung together into long rods.
Dong
Gang
G
Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06510, USA.
Hutagalung
Alex H
AH
Fu
Chunmei
C
Novick
Peter
P
Reinisch
Karin M
KM
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D003461:Crystallography; D005089:Exocytosis; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D022142:Secretory Vesicles / Q000737:chemistry; D033921:Vesicular Transport Proteins; D020741:rho GTP-Binding Proteins / Q000737:chemistry
C103132:EXO70 protein, S cerevisiae; C120810:EXO84 protein, S cerevisiae; D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); C074647:RHO3 protein, S cerevisiae; D020741:rho GTP-Binding Proteins