COG lobe B sub-complex engages v-SNARE GS15 and functions via regulated interaction with lobe A sub-complex

Sci Rep. 2016 Jul 7;6:29139. doi: 10.1038/srep29139.

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Cell Membrane / metabolism
  • Glycosylation
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Intracellular Membranes / metabolism
  • Models, Biological
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / metabolism*
  • Protein Binding
  • Protein Multimerization
  • Protein Stability
  • Protein Subunits / metabolism
  • Protein Transport
  • Qc-SNARE Proteins / chemistry
  • Qc-SNARE Proteins / metabolism*
  • Secretory Vesicles / metabolism

Substances

  • BET1L protein, human
  • Multiprotein Complexes
  • Protein Subunits
  • Qc-SNARE Proteins