title: Structural analysis of conserved oligomeric Golgi complex subunit 2.
abstract: The conserved oligomeric Golgi (COG) complex is strongly implicated in retrograde vesicular trafficking within the Golgi apparatus. Although its mechanism of action is poorly understood, it has been proposed to function by mediating the initial physical contact between transport vesicles and their membrane targets. An analogous role in tethering vesicles has been suggested for at least six additional large multisubunit complexes, including the exocyst, a complex essential for trafficking to the plasma membrane. Here we report the solution structure of a large portion of yeast Cog2p, one of eight subunits composing the COG complex. The structure reveals a six-helix bundle with few conserved surface features but a general resemblance to recently determined crystal structures of four different exocyst subunits. This finding provides the first structural evidence that COG, like the exocyst and potentially other tethering complexes, is constructed from helical bundles. These structures may represent platforms for interaction with other trafficking proteins including SNAREs (soluble N-ethylmaleimide factor attachment protein receptors) and Rabs.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Lorraine F
authors.initials: LF
authors.lastname: Cavanaugh
authors.forename: Xiaocheng
authors.initials: X
authors.lastname: Chen
authors.forename: Brian C
authors.initials: BC
authors.lastname: Richardson
authors.forename: Daniel
authors.initials: D
authors.lastname: Ungar
authors.forename: Istvan
authors.initials: I
authors.lastname: Pelczer
authors.forename: Josep
authors.initials: J
authors.lastname: Rizo
authors.forename: Frederick M
authors.initials: FM
authors.lastname: Hughson
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry; D006056:Golgi Apparatus / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008565:Membrane Proteins / Q000737:chemistry*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D033921:Vesicular Transport Proteins
chemical_list: C112749:COG2 protein, S cerevisiae; D005656:Fungal Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins