A Mechanism for Ca2+/Calmodulin-Dependent Protein Kinase II Clustering at Synaptic and Nonsynaptic Sites Based on Self-Association

The activity of Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays an integral role in regulating synaptic development and plasticity. We designed a live-cell-imaging approach to monitor an activity-dependent clustering of green fluorescent protein (GFP)-CaMKII holoenzymes, termed self-assoc...

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Bibliographic Details
Published in:The Journal of neuroscience 2005-07, Vol.25 (30), p.6971-6983
Main Authors: Hudmon, Andy, LeBel, Eric, Roy, Hugo, Sik, Attila, Schulman, Howard, Waxham, M. Neal, De Koninck, Paul
Format: Article
Language:English
Subjects:
Animals
Calcium - metabolism
Calcium-Calmodulin-Dependent Protein Kinase Type 2
Calcium-Calmodulin-Dependent Protein Kinases - chemistry
Calcium-Calmodulin-Dependent Protein Kinases - genetics
Calcium-Calmodulin-Dependent Protein Kinases - metabolism
Cell Membrane - metabolism
Cell Membrane - ultrastructure
Cells, Cultured
Cellular/Molecular
Green Fluorescent Proteins - genetics
Hippocampus - cytology
Humans
Hydrogen-Ion Concentration
Kidney - cytology
Neurons - enzymology
Phosphorylation
Protein Structure, Tertiary
Rats
Receptors, Glutamate - physiology
Synapses - enzymology
Threonine - metabolism
Transfection
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Summary:The activity of Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays an integral role in regulating synaptic development and plasticity. We designed a live-cell-imaging approach to monitor an activity-dependent clustering of green fluorescent protein (GFP)-CaMKII holoenzymes, termed self-association, a process that we hypothesize contributes to the translocation of CaMKII to synaptic and nonsynaptic sites in activated neurons. We show that GFP-CaMKII self-association in human embryonic kidney 293 (HEK293) cells requires a catalytic domain and multimeric structure, requires Ca2+ stimulation and a functional Ca2+/CaM-binding domain, is regulated by cellular pH and Thr286 autophosphorylation, and has variable rates of dissociation depending on Ca2+ levels. Furthermore, we show that the same rules that govern CaMKII self-association in HEK293 cells apply for extrasynaptic and postsynaptic translocation of GFP-CaMKII in hippocampal neurons. Our data support a novel mechanism for targeting CaMKII to postsynaptic sites after neuronal activation. As such, CaMKII may form a scaffold that, in combination with other synaptic proteins, recruits and localizes additional proteins to the postsynaptic density. We discuss the potential function of CaMKII self-association as a tag of synaptic activity.
ISSN:0270-6474
1529-2401
DOI:10.1523/JNEUROSCI.4698-04.2005