Rab22B's role in trans-Golgi network membrane dynamics

Biochem Biophys Res Commun. 2007 Sep 28;361(3):751-7. doi: 10.1016/j.bbrc.2007.07.076. Epub 2007 Jul 30.

Abstract

The small GTPase Rab22B (or Rab31) has been suspected to be involved in trafficking at trans-Golgi network. However, its exact cellular localization, tissue expression profile, and functions have not been uncharacterized. Specific antibody raised against Rab22B's protein revealed that Rab22B is brain-enriched, but is also present in substantial levels in spleen and intestine. In HeLa cells, endogenous Rab22B is largely associated with the trans-Golgi network (TGN). Over-expression of a GDP-binding mutant (Rab22BSN), but not wild-type Rab22B, specifically disrupts the TGN localization of TGN46, a dynamic marker which cycles between the TGN and the plasma membrane. The TGN resident membrane protein syntaxin 16, cis-Golgi markers such as GM130 and syntaxin 5, as well as the TGN/late endosome marker mannose 6-phosphate receptor (M6PR) are not affected by Rab22BSN, neither was endosomal-TGN transport of the Shiga toxin B subunit. The disruption of TGN46 staining by Rab22BSN could be specifically attributed to a domain at the C-terminal portion of Rab22B, where its sequence deviates the most from Rab22A. Over-expression of Rab22BSN inhibits the cell surface transport of the vesicular stomatitis virus G protein. Thus, Rab22B may have a role in anterograde exit from the TGN.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / immunology
  • Antibody Specificity
  • Cell Membrane / metabolism
  • Cells, Cultured
  • HeLa Cells
  • Humans
  • Immunohistochemistry
  • Mice
  • Protein Transport / physiology*
  • Rabbits
  • Rats
  • Transfection
  • rab GTP-Binding Proteins / metabolism
  • rab GTP-Binding Proteins / physiology*
  • trans-Golgi Network / physiology*

Substances

  • Antibodies
  • RAB22A protein, human
  • RAB31 protein, human
  • rab GTP-Binding Proteins