Subcellular distribution of the Rho-GEF Lfc in primate prefrontal cortex: effect of neuronal activation.
The strength of synaptic connections in the brain varies with activity, and this plasticity depends on remodeling of the actin cytoskeleton in dendritic spines. Critical to this are the Rho family GTPases, whose activity is controlled by various modulatory proteins, including the Rho-GEF Lfc. In cultured neurons and nonneuronal cells, Lfc has been shown both to bind to microtubules and to regulate the actin cytoskeleton. Significantly, Lfc was found to be concentrated in the dendritic shafts of cultured hippocampal neurons under control conditions but then translocated into spines when neural activity was stimulated. In this study, we used immunohistochemistry and electron microscopy to examine activity-dependent changes in the distribution of Lfc in the neuropil of monkey prefrontal cortex. We found that, although Lfc was concentrated in dendrites, it also had a complex distribution in the neuropil, including being present in spines, axons, terminals, and glial processes. Moreover, Lfc distribution varied in different layers of cortex. By using an in vitro slice preparation of monkey prefrontal cortex, we demonstrated an activity-dependent translocation of Lfc from dendritic shafts to spines. The results of this study support a role for Lfc in activity-dependent spine plasticity and demonstrate the feasibility of studying activity-dependent changes in protein localization in tissue slices.
Muly
E Chris
EC
Department of Psychiatry and Behavioral Sciences, Yerkes National Primate Research Center, Atlanta, Georgia 30322, USA. emuly@emory.edu
Nairn
Angus C
AC
Greengard
Paul
P
Rainnie
Donald G
DG
D000818:Animals; D000831:Animals, Newborn; D049229:Dendritic Spines / Q000378:metabolism / Q000648:ultrastructure; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D020662:Guanine Nucleotide Exchange Factors / Q000172:deficiency / Q000378:metabolism*; D066298:In Vitro Techniques; D008253:Macaca mulatta / Q000033:anatomy & histology; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D018345:Mice, Knockout; D016253:Microscopy, Immunoelectron; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure*; D019581:Neuropil / Q000378:metabolism / Q000648:ultrastructure*; D018408:Patch-Clamp Techniques / Q000379:methods; D010852:Picrotoxin / Q000494:pharmacology; D017397:Prefrontal Cortex / Q000033:anatomy & histology*; D011518:Proto-Oncogene Proteins / Q000172:deficiency; D064067:Rho Guanine Nucleotide Exchange Factors; D013347:Subcellular Fractions / Q000378:metabolism
D018690:Excitatory Amino Acid Agonists; D018756:GABA Antagonists; D020662:Guanine Nucleotide Exchange Factors; D016202:N-Methylaspartate; D010852:Picrotoxin; D011518:Proto-Oncogene Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; C577402:Arhgef2 protein, mouse