Involvement of Golgin-160 in cell surface transport of renal ROMK channel: co-expression of Golgin-160 increases ROMK currents

Cell Physiol Biochem. 2006;17(1-2):1-12. doi: 10.1159/000091454. Epub 2006 Feb 7.

Abstract

The weak inward rectifier potassium channel ROMK is important for water and salt reabsorption in the kidney. Here we identified Golgin-160 as a novel interacting partner of the ROMK channel. By using yeast two-hybrid assays and co-immunoprecipitations from transfected cells, we demonstrate that Golgin-160 associates with the ROMK C-terminus. Immunofluorescence microscopy confirmed that both proteins are co-localized in the Golgi region. The interaction was further confirmed by the enhancement of ROMK currents by the co-expressed Golgin-160 in Xenopus oocytes. The increase in ROMK current amplitude was due to an increase in cell surface density of ROMK protein. Golgin-160 also stimulated current amplitudes of the related Kir2.1, and of voltage-gated Kv1.5 and Kv4.3 channels, but not the current amplitude of co-expressed HERG channel. These results demonstrate that the Golgi-associated Golgin-160 recognizes the cytoplasmic C-terminus of ROMK, thereby facilitating the transport of ROMK to the cell surface. However, the stimulatory effect on the activity of more distantly-related potassium channels suggests a more general role of Golgin-160 in the trafficking of plasma membrane proteins.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Autoantigens / genetics
  • Autoantigens / metabolism*
  • Binding Sites
  • Biological Transport, Active
  • COS Cells
  • Cell Line
  • Chlorocebus aethiops
  • Female
  • Gene Library
  • Golgi Matrix Proteins
  • Humans
  • In Vitro Techniques
  • Kidney / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Multiprotein Complexes
  • Oocytes / metabolism
  • Potassium Channels, Inwardly Rectifying / chemistry
  • Potassium Channels, Inwardly Rectifying / genetics
  • Potassium Channels, Inwardly Rectifying / metabolism*
  • Rats
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Two-Hybrid System Techniques
  • Xenopus laevis

Substances

  • Autoantigens
  • GOLGA3 protein, human
  • Golgi Matrix Proteins
  • KCNJ1 protein, human
  • Kcnj1 protein, rat
  • Membrane Proteins
  • Multiprotein Complexes
  • Potassium Channels, Inwardly Rectifying
  • Recombinant Proteins