title: COG lobe B sub-complex engages v-SNARE GS15 and functions via regulated interaction with lobe A sub-complex.
abstract: The conserved oligomeric Golgi (COG) complex is a peripheral membrane protein complex which orchestrates tethering of intra-Golgi vesicles. We found that COG1-4 (lobe A) and 5-8 (lobe B) protein assemblies are present as independent sub-complexes on cell membranes. Super-resolution microscopy demonstrates that COG sub-complexes are spatially separated on the Golgi with lobe A preferential localization on Golgi stacks and the presence of lobe B on vesicle-like structures, where it physically interacts with v-SNARE GS15. The localization and specific interaction of the COG sub-complexes with the components of vesicle tethering/fusion machinery suggests their different roles in the vesicle tethering cycle. We propose and test a novel model that employs association/disassociation of COG sub-complexes as a mechanism that directs vesicle tethering at Golgi membranes. We demonstrate that defective COG assembly or restriction of tethering complex disassembly by a covalent COG1-COG8 linkage is inhibitory to COG complex activity, supporting the model.
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Rose
authors.initials: R
authors.lastname: Willett
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Jessica Bailey
authors.initials: JB
authors.lastname: Blackburn
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Climer
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Pokrovskaya
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Tetyana
authors.initials: T
authors.lastname: Kudlyk
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Physiology and Biophysics, UAMS, Little Rock, AR, USA.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Lupashin
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008954:Models, Biological; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D055503:Protein Multimerization; D055550:Protein Stability; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport; D050767:Qc-SNARE Proteins / Q000737:chemistry / Q000378:metabolism*; D022142:Secretory Vesicles / Q000378:metabolism
chemical_list: C107588:BET1L protein, human; D046912:Multiprotein Complexes; D021122:Protein Subunits; D050767:Qc-SNARE Proteins