Evidence that Ser-82 is a unique phosphorylation site on vimentin for CA2+-calmodulin-dependent protein kinase II

Ando, Shoji; Tokui, Toshiya; Yamauchi, Takashi; Sugiura, Hiroko; Tanabe, Kazushi; Inagaki, Masaki

doi:10.1016/0006-291x(91)91658-y

Cited by 63 publications

(39 citation statements)

References 25 publications

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“…To begin to address this issue we took advantage of the existence of a sequence derived from the head region of vimentin (Vim) containing a dedicated CaMKII phosphorylation site at Ser 82 (21). The short sequence (88 amino acids) of Vim containing Ser 82 is a highly specific substrate for CaMKII in that it is not phosphorylated by any other major Ser/Thr kinases, including CaMKI, CaMKIV, PKC, cdc2, and PKA (21)(22)(23). Importantly, in both heterologous cells and neurons, via the immunocytochemical detection of a specific antibody against the phosphorylated form of Ser 82 , ectopically expressed Vim has proved to be a sensitive probe for CaMKII activity (17,21).…”

Section: Resultsmentioning

confidence: 99%

Substrate Localization Creates Specificity in Calcium/Calmodulin-dependent Protein Kinase II Signaling at Synapses

Tsui

Malenka

2006

Journal of Biological Chemistry

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Calcium/calmodulin-dependent protein kinase II (CaMKII), a major component of the postsynaptic density (PSD) of excitatory synapses, plays a key role in the regulation of synaptic function in the mammalian brain. Although many postsynaptic substrates for CaMKII have been characterized in vitro, relatively little is known about their phosphorylation in vivo. By tagging synaptic proteins with a peptide substrate specific for CaMKII and expressing them in cultured neurons, we have visualized substrate phosphorylation by CaMKII at intact synapses. All substrates tested were strongly phosphorylated by CaMKII in HEK293 cells. However, activity-dependent phosphorylation of substrates at synapses was highly selective in that the glutamate receptor subunits NR2B and GluR1 were poorly phosphorylated whereas PSD-95 and Stargazin, proteins implicated in the scaffolding and trafficking of AMPA receptors, were robustly phosphorylated. Phosphatase activity limited phosphorylation of Stargazin but not NR2B and GluR1. These results suggest that the unique molecular architecture of the PSD results in highly selective substrate discrimination by CaMKII.Calcium-calmodulin-dependent protein kinase II (CaMKII) 2 is a major effecter for calcium-dependent signaling in neurons. It has been implicated in dendritic filapodial extension (1), presynaptic plasticity (2), retrograde signaling to the presynaptic terminal (3), and most notably, the phenomenon of long-term potentiation (LTP) (4, 5), the leading model for a synaptic mechanism underlying learning and memory (6). Although several candidates have been proposed to mediate the synaptic consequences of activating CaMKII (7), it has been difficult to characterize how synaptic proteins are phosphorylated by CaMKII when incorporated into functioning synapses. This is a particularly important and challenging issue because biochemical and proteomic approaches to identifying CaMKII substrates in the postsynaptic density (PSD), the electron dense postsynaptic specialization that contains glutamate receptors and associated signaling machinery, have found at least 28 potential substrate proteins (8). Furthermore, it is unknown whether stimulus-dependent substrate specificity is an inherent property of the PSD and whether the source of the calcium that activates CaMKII and protein phosphatase activity influence synaptic substrate phosphorylation.Some recent evidence suggests that the intricate scaffolding of proteins within different levels of the PSD may influence CaMKII signal transduction. First, electron microscopy studies on isolated PSDs have revealed both a laminar and heterogeneous distribution of CaMKII on the cytosolic face, suggesting that CaMKII may be specifically positioned to exert its activity on nanodomains within this macromolecular complex (9). Second, CaMKII interactions with the NMDA receptor (NMDAR) subunit NR2B (10) and the Drosophila homolog of CASK, Cmg (11), a member of the MAGUK family of synaptic scaffolding proteins (12), have both been found to influence its state o...

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Section: Resultsmentioning

confidence: 99%

Substrate Localization Creates Specificity in Calcium/Calmodulin-dependent Protein Kinase II Signaling at Synapses

Tsui

Malenka

2006

Journal of Biological Chemistry

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“…Vimentin is an intermediate filament protein, the assembly of which is regulated by phosphorylation of several protein kinases at multiple sites. One of these sites, Ser-82, has been characterized as a substrate for CaMKII, but not other kinases, including CaMKI, CaMKIV, protein kinase C, and cAMP-dependent protein kinase (25)(26)(27). Using an antibody against the phosphorylated form of Ser-82, ectopically expressed vimentin has proved to be a sensitive probe for CaMKII activity both in heterologous cells and in neurons (25).…”

Section: Resultsmentioning

confidence: 99%

Calcium/Calmodulin-dependent Protein Kinase II (CaMKII) Localization Acts in Concert with Substrate Targeting to Create Spatial Restriction for Phosphorylation

Tsui

Inagaki

Schulman

2005

Journal of Biological Chemistry

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Ca2؉ /calmodulin-dependent protein kinase II (CaMKII) acts in diverse cell types by phosphorylating proteins with key calcium-dependent functions such as synaptic plasticity, electrical excitability, and neurotransmitter synthesis. CaMKII displays calcium-dependent binding to proteins in vitro and translocation to synaptic sites after glutamatergic activity in neurons. We therefore hypothesized that subcellular targeting of CaMKII can direct its substrate specificity in an activitydependent fashion. Here, we examined whether activitydependent colocalization of CaMKII and its substrates could result in regulation of substrate phosphorylation in cells. We find that substrates localized at cellular membranes required CaMKII translocation to these compartments to achieve effective phosphorylation. Spatial barriers to phosphorylation could be overcome by translocation and anchoring to the substrate itself or to nearby target proteins within the membrane compartment. In contrast, phosphorylation of a cytoplasmic counterpart of the substrate does not require CaMKII translocation or stable protein-protein binding. Cytosolic phosphorylation is more permissive, exhibiting partial calcium-independence. Localization-dependent substrate specificity can also show more graded levels of regulation within signaling microdomains. We find that colocalization of translocated CaMKII and its substrate to lipid rafts in the plasma membrane can modulate the magnitude of phosphorylation. Thus, dynamic regulation of both substrate and kinase localization provides a powerful and nuanced way to regulate CaMKII signal specificity. Ca2ϩ /calmodulin-dependent protein kinase II (CaMKII) 1 is a multifunctional serine/threonine kinase important for a variety of cellular functions including cell division, differentiation, cardiac contraction, and synaptic plasticity (1). CaMKII is required for long term potentiation at CA1 synapses as well as in behavioral learning and memory tasks (2-4). A number of the prominent CaMKII substrates are membrane proteins. CaMKII phosphorylation of the AMPA receptor (AMPAR), ryanodine receptor, and several ion channels regulate their conductance properties (5-7). Thus, CaMKII has a wide repertoire of substrates and associated cellular functions, which raises the question of how CaMKII activity can discriminate among its many substrates. A possible point of regulation could be through the complex subcellular targeting of CaMKII.Several mechanisms of CaMKII subcellular targeting have been characterized as CaMKII splice variants and isoforms can contain targeting sequences such as a nuclear localization sequence and actin binding domains (8, 9). Membrane targeting can be mediated by assembly with proteins such as ␣CaMKII association protein (10). Recently, CaMKII has shown calcium/ calmodulin-dependent interactions with membrane proteins such as the NMDA receptor 2B subunit (NR2B) that can affect its distribution in heterologous cells (11,12). Activity-dependent CaMKII translocation in neurons has also been observed. ...

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“…39) CaM kinase II also phosphorylates Ser or Thr of the sequence S/TXD, which is a completely different sequence from the major consensus site. 40) Therefore, CaM kinase II has extremely broad substrate specificity, phosphorylates a broad range of brain proteins, and plays many important roles in the functions of the brain. -independent enzymes.…”

Section: Enzymatic Propertiesmentioning

confidence: 99%

Neuronal Ca2+/Calmodulin-Dependent Protein Kinase II-Discovery, Progress in a Quarter of a Century, and Perspective: Implication for Learning and Memory

Yamauchi

2005

Biological & Pharmaceutical Bulletin

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184

125

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Much has been learned about the activity-dependent synaptic modifications that are thought to underlie memory storage, but the mechanism by which these modifications are stored remains unclear. A good candidate for the storage mechanism is Ca 2؉ /calmodulin-dependent protein kinase II (CaM kinase II). CaM kinase II is one of the most prominent protein kinases, present in essentially every tissue but most concentrated in brain. Although it has been about a quarter of a century since the finding, CaM kinase II has been of the major interest in the region of brain science. It plays a multifunctional role in many intracellular events, and the expression of the enzyme is carefully regulated in brain regions and during brain development. Neuronal CaM kinase II regulates important neuronal functions, including neurotransmitter synthesis, neurotransmitter release, modulation of ion channel activity, cellular transport, cell morphology and neurite extension, synaptic plasticity, learning and memory, and gene expression. Studies concerning this kinase have provided insight into the molecular basis of nerve functions, especially learning and memory, and indicate one direction for studies in the field of neuroscience. This review presents the molecular structure, properties and functions of CaM kinase II, as a major component of neurons, based mainly developed on findings made in our laboratory.

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Evidence that Ser-82 is a unique phosphorylation site on vimentin for CA2+-calmodulin-dependent protein kinase II

Cited by 63 publications

References 25 publications

Substrate Localization Creates Specificity in Calcium/Calmodulin-dependent Protein Kinase II Signaling at Synapses

Substrate Localization Creates Specificity in Calcium/Calmodulin-dependent Protein Kinase II Signaling at Synapses

Calcium/Calmodulin-dependent Protein Kinase II (CaMKII) Localization Acts in Concert with Substrate Targeting to Create Spatial Restriction for Phosphorylation

Neuronal Ca2+/Calmodulin-Dependent Protein Kinase II-Discovery, Progress in a Quarter of a Century, and Perspective: Implication for Learning and Memory

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