CaMKIIbeta functions as an F-actin targeting module that localizes CaMKIIalpha/beta heterooligomers to dendritic spines.
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a serine/threonine protein kinase that regulates long-term potentiation and other forms of neuronal plasticity. Functional differences between the neuronal CaMKIIalpha and CaMKIIbeta isoforms are not yet known. Here, we use green fluorescent protein-tagged (GFP-tagged) CaMKII isoforms and show that CaMKIIbeta is bound to F-actin in dendritic spines and cell cortex while CaMKIIalpha is largely a cytosolic enzyme. When expressed together, the two isoforms form large heterooligomers, and a small fraction of CaMKIIbeta is sufficient to dock the predominant CaMKIIalpha to the actin cytoskeleton. Thus, CaMKIIbeta functions as a targeting module that localizes a much larger number of CaMKIIalpha isozymes to synaptic and cytoskeletal sites of action.
Department of Cell Biology, Duke University Medical Center Durham, North Carolina 27710, USA.
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Shen
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Teruel
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Subramanian
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Meyer
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism*; D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003599:Cytoskeleton / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D007527:Isoenzymes / Q000032:analysis / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D046911:Macromolecular Substances; D051379:Mice; D009412:Nerve Fibers / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D014176:Protein Biosynthesis; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D000199:Actins; D007527:Isoenzymes; D008164:Luminescent Proteins; D046911:Macromolecular Substances; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases