Somatodendritic localization of EFA6A, a guanine nucleotide exchange factor for ADP-ribosylation factor 6, and its possible interaction with alpha-actinin in dendritic spines

Eur J Neurosci. 2007 Feb;25(3):618-28. doi: 10.1111/j.1460-9568.2007.05345.x. Epub 2007 Feb 12.


EFA6A is a member of the guanine nucleotide exchange factors that can specifically activate ADP ribosylation factor 6 (ARF6). In this study, we identified alpha-actinin-1 as a possible interacting protein with EFA6A by the yeast two-hybrid screening with its C-terminal region as bait. The central region of alpha-actinin-1 containing a part of spectrin repeat 1 and spectrin repeats 2-3 is responsible for this interaction. In the hippocampal formation, EFA6A immunoreactivity occurred at a high level as numerous fine puncta in the strata oriens, radiatum, lacunosum-moleculare of the hippocampal CA1-3 subfields and the dentate molecular layer, whereas the immunoreactivity was faint in the neuronal cell layers and the stratum lucidum, the mossy fiber-recipient layer of the CA3 subfield. Double-immunofluorescent analyses revealed a partial overlapping of EFA6A and alpha-actinin at the dendritic spines of in vivo and cultured hippocampal neurons. Our present findings suggest that EFA6A may form a protein complex with alpha-actinin and activate ARF6 in close proximity of the actin cytoskeleton and membrane proteins in the dendritic spines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ADP-Ribosylation Factors / metabolism*
  • Actinin / metabolism*
  • Animals
  • Antibodies
  • COS Cells
  • Cells, Cultured
  • Chlorocebus aethiops
  • Dendritic Spines / metabolism*
  • Guanine / metabolism
  • Guanine Nucleotide Exchange Factors / genetics*
  • Guanine Nucleotide Exchange Factors / immunology
  • Guanine Nucleotide Exchange Factors / metabolism*
  • Hippocampus / cytology
  • Hippocampus / physiology
  • Immunohistochemistry
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neurons / physiology
  • Neurons / ultrastructure
  • Protein Binding / physiology
  • Rabbits
  • Two-Hybrid System Techniques
  • Yeasts


  • Antibodies
  • Guanine Nucleotide Exchange Factors
  • Psd protein, mouse
  • Actinin
  • Guanine
  • ADP-Ribosylation Factors
  • ADP-ribosylation factor 6