Activity-driven mobilization of post-synaptic proteins.
Synapses established during central nervous system development can be modified through synapse elimination and formation. These processes are, in part, activity dependent and require regulated trafficking of post-synaptic components. Here, we investigate the activity-driven remodeling of cultured rat hippocampal neurons at 14 days in vitro, focusing on the post-synaptic proteins PSD-95, Shank, neuroligin (NL)1 and actin. Using live imaging and photoconductive stimulation, we found that high-frequency activity altered the trajectory, but not velocity, of PSD-95-GFP and Shank-YFP clusters, whereas it reduced the speed and increased the number of NL1 clusters. Actin-CFP reorganized into puncta following activity and approximately 50% of new puncta colocalized with NL1 clusters. Actin reorganization was enhanced by the overexpression of NL1 and decreased by the expression of an NL1 mutant, NL1-R473C. These results demonstrate activity-dependent changes that may result in the formation of new post-synaptic sites and suggest that NL1 modulates actin reorganization. The results also suggest that a common mechanism underlies both the developmental and activity-dependent remodeling of excitatory synapses.
Department of Physiology, University of Calgary, Calgary, AB, Canada.
R Carolina
RC
Gutiérrez
Robyn
R
Flynn
Johanna
J
Hung
Audrey C
AC
Kertesz
Andrea
A
Sullivan
Gerald W
GW
Zamponi
Alaa
A
El-Husseini
Michael A
MA
Colicos
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D020410:Activated-Leukocyte Cell Adhesion Molecule / Q000235:genetics / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002452:Cell Count / Q000379:methods; D000076122:Disks Large Homolog 4 Protein; D004307:Dose-Response Relationship, Radiation; D005786:Gene Expression Regulation / Q000502:physiology* / Q000528:radiation effects; D006624:Hippocampus / Q000166:cytology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins; D009474:Neurons / Q000378:metabolism*; D010775:Photic Stimulation / Q000379:methods; D021381:Protein Transport / Q000502:physiology / Q000528:radiation effects; D050683:R-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection / Q000379:methods
D000199:Actins; D020410:Activated-Leukocyte Cell Adhesion Molecule; D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050683:R-SNARE Proteins