Interactions between Neurogranin and Calmodulin in Vivo

Prichard, Lisa; Deloulme, Jean-Christophe; Storm, Daniel R.

doi:10.1074/jbc.274.12.7689

Cited by 95 publications

(87 citation statements)

References 56 publications

(44 reference statements)

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“…We also studied the interaction of CaM with the full C-terminal region of SK2 potassium channel as well as neurogranin and the C-terminal region of P/Q calcium channel for reference (16,21,29). As previously reported, we found that the C-terminal lobe of CaM (aa 78 -148, EF-3,4) interacted with the C-terminal domain of SK2 (21).…”

Section: Determinants In Cam That Are Required For Binding Tomentioning

confidence: 50%

“…Mutating Ser 36 3 Ala of neurogranin makes the IQ motif of neurogranin resemble that of KCNQ2 and does not affect (or may even increase) CaM binding. However, mutating Ser 36 3 Asp, thereby introducing a negative charge that mimics the effect of protein kinase C, abolishes the interaction between neurogranin and CaM in the two-hybrid assay (16). Similarly, we found that the interaction between CaM and the KCNQ2 bait was lost in the equivalent Ala 343 3 Asp mutant.…”

Section: Cammentioning

confidence: 51%

“…It should be born in mind that a limitation of the two-hybrid system is that the transmembrane segments of target proteins must be eliminated to allow targeting of the bait to the nucleus (34). However, the main advantage is that this is a relatively simple assay and that it does offer us the opportunity to study proteinprotein interactions in a living cell (16).…”

Section: Discussionmentioning

confidence: 99%

“…3A). Mutations within the IQ motif have been shown to abolish the interaction between CaM and neurogranin in a two-hybrid assay (16) or to alter the Ca 2ϩ -dependent regulation of ion channels (17). We introduced several point mutations to determine whether amino acids within the IQ domain are necessary for the interaction of KCNQ2 with CaM.…”

Section: Cammentioning

confidence: 99%

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The Identification and Characterization of a Noncontinuous Calmodulin-binding Site in Noninactivating Voltage-dependent KCNQ Potassium Channels

Yus-Nájera

Santana-Castro

Villarroel

2002

Journal of Biological Chemistry

187

266

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We show here that in a yeast two-hybrid assay calmodulin (CaM) interacts with the intracellular C-terminal region of several members of the KCNQ family of potassium channels. CaM co-immunoprecipitates with KCNQ2, KCNQ3, or KCNQ5 subunits better in the absence than in the presence of Ca 2؉ . Moreover, in twohybrid assays where it is possible to detect interactions with apo-CaM but not with Ca 2؉ -bound calmodulin, we localized the CaM-binding site to a region that is predicted to contain two ␣-helices (A and B). These two helices encompass ϳ85 amino acids, and in KCNQ2 they are separated by a dispensable stretch of ϳ130 amino acids. Within this CaM-binding domain, we found an IQ-like CaM-binding motif in helix A and two overlapping consensus 1-5-10 CaM-binding motifs in helix B. Point mutations in helix A or B were capable of abolishing CaM binding in the two-hybrid assay. Moreover, glutathione S-transferase fusion proteins containing helices A and B were capable of binding to CaM, indicating that the interaction with KCNQ channels is direct. Fulllength CaM (both N and C lobes) and a functional EF-1 hand were required for these interactions to occur. These observations suggest that apo-CaM is bound to neuronal KCNQ channels at low resting Ca 2؉ levels and that this interaction is disturbed when the [Ca 2؉ ] is raised. Thus, we propose that CaM acts as a mediator in the Ca 2؉ -dependent modulation of KCNQ channels.The KCNQ transmembrane proteins are members of a family of voltage-dependent potassium selective channels that are involved in the control of cellular excitability. Remarkably, mutations in four of the five known members of this family have been associated with different hereditary human disorders. While mutations in the KCNQ1 subunit (KvQT1) lead to arrhythmia in the human long QT syndrome, mutations in KCNQ2 or KCNQ3 are associated with a benign form of epilepsy. It has also been shown that KCNQ4 is mutated in a dominant form of progressive hearing loss (1).With regards to the normal physiology of this protein family, the KCNQ2 and KCNQ3 subunits have been shown to form M-type potassium channels whose expression is restricted to neuronal tissue (2). Moreover, in some brain areas and neuronal tissues, KCNQ4 and KCNQ5 also contribute to the formation of M channels, suggesting that the different combinations of KCNQ subunits may be in part responsible for the diversity of M channel properties (1). The M current (I M ) is a subthreshold noninactivating voltage-dependent potassium current that is found in many neuronal cell types. The M current controls membrane excitability, and it has been shown to be modulated by a variety of intracellular signals that in turn dramatically affect the firing rate of neurons. Among those intracellular signals, Ca 2ϩ has been shown to mediate the inhibition of I M by B 2 bradykinin receptors in sympathetic neurons (3). Indeed, intracellular Ca 2ϩ can suppress the activity of M channels under conditions that do not support enzymatic activities such as phosphorylation (4). Th...

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Section: Determinants In Cam That Are Required For Binding Tomentioning

confidence: 50%

Section: Cammentioning

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Section: Cammentioning

confidence: 99%

See 2 more Smart Citations

The Identification and Characterization of a Noncontinuous Calmodulin-binding Site in Noninactivating Voltage-dependent KCNQ Potassium Channels

Yus-Nájera

Santana-Castro

Villarroel

2002

Journal of Biological Chemistry

187

266

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“…This protein has been implicated in the regulation of numerous postsynaptic signal transduction pathways because of its role in the regulation of Ca 2ϩ and CaM in neurons (1)(2)(3). The CaM-binding affinity of Ng is attenuated by phosphorylation with protein kinase C (PKC) and by oxidation with nitric oxide (NO) (4-7); both modifications have the potential to modulate neuronal free Ca 2ϩ and CaM levels.…”

mentioning

confidence: 99%

Involvement of neurogranin in the modulation of calcium/calmodulin-dependent protein kinase II, synaptic plasticity, and spatial learning: A study with knockout mice

Pak

Huang

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

231

229

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Neurogranin͞RC3 is a neural-specific Ca 2؉ -sensitive calmodulin (CaM)-binding protein whose CaM-binding affinity is modulated by phosphorylation and oxidation. Here we show that deletion of the Ng gene in mice did not result in obvious developmental or neuroanatomical abnormalities but caused an impairment of spatial learning and changes in hippocampal short-and long-term plasticity (paired-pulse depression, synaptic fatigue, long-term potentiation induction). These deficits were accompanied by a decreased basal level of the activated Ca 2؉ ͞CaM-dependent kinase II (CaMKII) (Ϸ60% of wild type). Furthermore, hippocampal slices of the mutant mice displayed a reduced ability to generate activated CaMKII after stimulation of protein phosphorylation and oxidation by treatments with okadaic acid and sodium nitroprusside, respectively. These results indicate a central role of Ng in the regulation of CaMKII activity with decisive influences on synaptic plasticity and spatial learning.

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Pre- and postsynaptic localization of RC3/neurogranin in the adult rat spinal cord: An immunohistochemical study

et al. 2000

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RC3 (neurogranin; BICKS) is a neuron-specific calmodulin-binding protein kinase C substrate. Thus far, immunohistochemical studies on the localization of RC3 revealed its presence in all neuronal phenotypes, which were restricted to specific areas in the neostriatum, the neocortex, and the hippocampus. RC3 was mostly found in cell bodies and dendrites, with some infrequent presence in axonal profiles, i.e. in the internal capsule. Until now, RC3 expression was reported to be absent in the adult rat spinal cord. RC3 might, however, act as an intermediate of protein kinase C-mediated signaling pathways during synaptic development and plasticity. We hypothesized a role for this 78-amino-acid protein in dendritic plasticity occurring after spinal cord injury. To our surprise, an immunohistological analysis of the uninjured adult rat spinal cord revealed the presence of RC3-positive cell bodies and dendrites in specific regions in the gray matter. Interestingly, axon-containing structures, such as the dorsal and ventral corticospinal tract, were also found to be RC3-positive. This axonal labeling was confirmed by preembedding electron microscopy. In conclusion, we demonstrate here that RC3 is present in the adult rat spinal cord in pre- and postsynaptic structures.

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Interactions between Neurogranin and Calmodulin in Vivo

Cited by 95 publications

References 56 publications

The Identification and Characterization of a Noncontinuous Calmodulin-binding Site in Noninactivating Voltage-dependent KCNQ Potassium Channels

The Identification and Characterization of a Noncontinuous Calmodulin-binding Site in Noninactivating Voltage-dependent KCNQ Potassium Channels

Involvement of neurogranin in the modulation of calcium/calmodulin-dependent protein kinase II, synaptic plasticity, and spatial learning: A study with knockout mice

Pre- and postsynaptic localization of RC3/neurogranin in the adult rat spinal cord: An immunohistochemical study

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