title: Multivalent interactions of calcium/calmodulin-dependent protein kinase II with the postsynaptic density proteins NR2B, densin-180, and alpha-actinin-2.
abstract: Dendritic calcium/calmodulin-dependent protein kinase II (CaMKII) is dynamically targeted to the synapse. We show that CaMKIIalpha is associated with the CaMKII-binding proteins densin-180, the N-methyl-D-aspartate receptor NR2B subunit, and alpha-actinin in postsynaptic density-enriched rat brain fractions. Residues 819-894 within the C-terminal domain of alpha-actinin-2 constitute the minimal CaMKII-binding domain. Similar amounts of Thr286-autophosphorylated CaMKIIalpha holoenzyme [P-T286]CaMKII bind to alpha-actinin-2 as bind to NR2B (residues 1260-1339) or to densin-180 (residues 1247-1495) in glutathione-agarose cosedimentation assays, even though the CaMKII-binding domains share no amino acid sequence similarity. Like NR2B, alpha-actinin-2 binds to representative splice variants of each CaMKII gene (alpha, beta, gamma, and delta), whereas densin-180 binds selectively to CaMKIIalpha. In addition, C-terminal truncated CaMKIIalpha monomers can interact with NR2B and alpha-actinin-2, but not with densin-180. Soluble alpha-actinin-2 does not compete for [P-T286]CaMKII binding to immobilized densin-180 or NR2B. However, soluble densin-180, but not soluble NR2B, increases CaMKII binding to immobilized alpha-actinin-2 by approximately 10-fold in a PDZ domain-dependent manner. A His6-tagged NR2B fragment associates with GST-densin or GST-actinin but only in the presence of [P-T286]CaMKII. Similarly, His6-tagged densin-180 or alpha-actinin fragments associate with GST-NR2B in a [P-T286]CaMKII-dependent manner. In addition, GST-NR2B and His6-tagged alpha-actinin can bind simultaneously to monomeric CaMKII subunits. In combination, these data support a model in which [P-T286]CaMKIIalpha can simultaneously interact with multiple dendritic spine proteins, possibly stabilizing the synaptic localization of CaMKII and/or nucleating a multiprotein synaptic signaling complex.
authors.affiliation: Department of Molecular Physiology and Biophysics, Center for Molecular Neuroscience, Vanderbilt-Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37232-0615, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Robison
authors.forename: Martha A
authors.initials: MA
authors.lastname: Bass
authors.forename: Yuxia
authors.initials: Y
authors.lastname: Jiao
authors.forename: Leigh B
authors.initials: LB
authors.lastname: MacMillan
authors.forename: Leigh C
authors.initials: LC
authors.lastname: Carmody
authors.forename: Ryan K
authors.initials: RK
authors.lastname: Bartlett
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Colbran
mesh_terms: D000185:Actinin / Q000737:chemistry*; D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D015153:Blotting, Western; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D005978:Glutathione / Q000737:chemistry; D005982:Glutathione Transferase / Q000378:metabolism; D006639:Histidine / Q000737:chemistry; D047468:Immunoprecipitation; D007313:Insecta; D046911:Macromolecular Substances / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000737:chemistry; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry* / Q000378:metabolism; D012685:Sepharose / Q000737:chemistry; D012795:Sialoglycoproteins / Q000737:chemistry*; D015398:Signal Transduction; D013552:Swine; D013569:Synapses / Q000378:metabolism; D013912:Threonine / Q000737:chemistry; D014981:Xenopus
chemical_list: C401401:ACTN2 protein, human; C504463:Lrrc7 protein, rat; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; C121001:NR2B NMDA receptor; D020033:Protein Isoforms; D016194:Receptors, N-Methyl-D-Aspartate; D012795:Sialoglycoproteins; D000185:Actinin; D013912:Threonine; D006639:Histidine; D012685:Sepharose; D005982:Glutathione Transferase; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D005978:Glutathione