Somatodendritic localization of EFA6A, a guanine nucleotide exchange factor for ADP-ribosylation factor 6, and its possible interaction with alpha-actinin in dendritic spines.
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.
Sakagami
Hiroyuki
H
Division of Histology, Department of Cell Biology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Sendai 980-8575, Japan. h-sakagami@mail.tains.tohoku.ac.jp
Honma
Takashi
T
Sukegawa
Jun
J
Owada
Yuji
Y
Yanagisawa
Teruyuki
T
Kondo
Hisatake
H
D000089982:ADP-Ribosylation Factor 6; D020727:ADP-Ribosylation Factors / Q000378:metabolism*; D000185:Actinin / Q000378:metabolism*; D000818:Animals; D000906:Antibodies; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D049229:Dendritic Spines / Q000378:metabolism*; D006147:Guanine / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D011485:Protein Binding / Q000502:physiology; D011817:Rabbits; D020798:Two-Hybrid System Techniques; D015003:Yeasts
D000089982:ADP-Ribosylation Factor 6; D000906:Antibodies; D020662:Guanine Nucleotide Exchange Factors; C504474:Psd protein, mouse; D000185:Actinin; D006147:Guanine; D020727:ADP-Ribosylation Factors; C000715727:Arf6 protein, mouse