Phosphorylation of calmodulin

Benaím, Gustavo; Villalobo, Antonio

doi:10.1046/j.1432-1033.2002.03038.x

Cited by 134 publications

(77 citation statements)

References 79 publications

(188 reference statements)

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“…Although CaM has been identified as a phosphoprotein in a few cell types (14), phosphorylation of CaM in endothelial cells has not been previously described to our knowledge. The interactions between eNOS and CaM have been extensively characterized, and in endothelial cells, it appears that eNOS plays a significant role in modulating diverse CaM-dependent processes by binding up to Ϸ25% of the limited pool of total cellular CaM (19).…”

mentioning

confidence: 82%

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Calmodulin phosphorylation and modulation of endothelial nitric oxide synthase catalysis

Greif

Sacks²,

Michel³

2004

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

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The endothelial NO synthase (eNOS) is regulated by diverse protein kinase pathways, yet eNOS activity ultimately depends on the ubiquitous calcium regulatory protein calmodulin (CaM). In these studies, we establish that CaM itself undergoes phosphorylation in endothelial cells and that CaM phosphorylation attenuates eNOS activation. Using [ 32 P]orthophosphoric acid biosynthetic labeling, we found that CaM is a phosphoprotein in bovine aortic endothelial cells (BAEC) and that the kinase CK2 promotes CaM phosphorylation in BAEC. Phosphorylation of CaM by purified CK2 in vitro reduces the V max of immunopurified eNOS by a factor of 2 but has no effect on the K A for CaM or calcium. Additionally, [ 32 P]orthophosphoric acid biosynthetic labeling of mutant CaM-transfected BAEC revealed that phosphorylation of Ser-81 to alanine mutant CaM (''phosphonull'' S81A mutant) is dramatically reduced relative to WT, whereas phosphorylation of the ''phosphomimetic'' Ser-81 to aspartate (S81D) mutant is unchanged. Further studies using Escherichia coli-expressed and phenylSepharose-purified CaM mutants revealed that the S81A mutation abrogates in vitro CK2-mediated phosphorylation of CaM, whereas phosphorylation of the S81D CaM mutant by CK2 is preserved. Additionally, we found that the phosphomimetic S101D CaM mutant is impaired in its ability to activate eNOS. Taken together, these results suggest that phosphorylation of CaM inhibits eNOS catalysis and proceeds in a hierarchical manner, initially requiring phosphorylation of the CaM Ser-81 residue. We conclude that CaM phosphorylation may represent a unique pathway in the regulation of eNOS signaling and thereby may play a role in modulating NO-dependent vascular responses.T he vascular system uses a network of cell signaling pathways to maintain a delicate homeostatic balance. The endothelial NO synthase (eNOS) is a calmodulin-dependent enzyme that plays a key role in many of these signaling cascades by catalyzing the conversion of L-arginine and oxygen to L-citrulline and the labile gas NO (1). Because NO has fundamental effects on many aspects of vascular physiology (2), it is not surprising that eNOS is tightly regulated by a number of mechanisms. Subcellular localization, acylation, phosphorylation, and direct interaction with other proteins, including calmodulin (CaM), caveolin, and heat shock protein 90, have been shown to modulate eNOS (3). Recently, the phosphorylation of eNOS in endothelial cells has been extensively characterized (4-9); however, the role of phosphorylation pathways in modulating the protein partners of eNOS, such as CaM, is much less well understood.CaM is a ubiquitously expressed, highly conserved acidic protein that mediates a broad range of intracellular calcium-regulated enzymes (10, 11), including eNOS (12). CaM is comprised of 148 aa and has a ''dumbbell'' structure: a long flexible central helix joining two pairs of calcium-binding helix-loop-helix motifs, known as EF hands (13). Upon binding calcium, CaM exposes hydrophobic regions on its s...

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confidence: 82%

“…Furthermore, CaM itself has been shown to be a phosphoprotein (reviewed in ref. 14 (15)(16)(17) and has been implicated in insulin-induced CaM phosphorylation in hepatocytes (18).…”

mentioning

confidence: 99%

Calmodulin phosphorylation and modulation of endothelial nitric oxide synthase catalysis

Greif

Sacks²,

Michel³

2004

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

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“…Overall, CaM seems to be a limiting factor in cell function (119). Furthermore, the CaM protein has been shown to undergo posttranslational modifications including acetylation, trimethylation, carboxylmethylation, proteolytic cleavage, and phosphorylation (120)(121)(122). These chemical modifications may modulate CaM's biological activity as a Ca 2ϩ sensor protein; however, the physiological roles of such posttranslational events remain to be fully explored.…”

Section: Cellular Level Of Controlmentioning

confidence: 99%

Genetic polymorphism and protein conformational plasticity in the calmodulin superfamily: Two ways to promote multifunctionality

Ikura

Ames

2006

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

239

202

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Calcium signaling pathways control a variety of cellular events such as gene transcription, protein phosphorylation, nucleotide metabolism, and ion transport. These pathways often involve a large number of calcium-binding proteins collectively known as the calmodulin or EF-hand protein superfamily. Many EF-hand proteins undergo a large conformational change upon binding to Ca 2؉ and target proteins. All members of the superfamily share marked sequence homology and similar structural features required to sense Ca 2؉ . Despite such structural similarities, the functional diversity of EF-hand calcium-binding proteins is extraordinary. Calmodulin itself can bind >300 different proteins, and the many members of the neuronal calcium sensor and S100 protein families collectively recognize a largely different set of target proteins. Recent biochemical and structural studies of many different EF-hand proteins highlight remarkable similarities and variations in conformational responses to the common ligand Ca 2؉ and their respective cellular targets. In this review, we examine the essence of molecular recognition activities and the mechanisms by which calmodulin superfamily proteins control a wide variety of Ca 2؉ signaling processes.

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“…Light-dependent phosphorylation regulates the physiological activity of several key players in the phototransduction cascade, including rhodopsin, opsin, phosducin, RGS-9 (regulator of G-protein signaling 9), centrins, ␤-subunit of the insulin receptor, abLIM (actin binding LIM protein family), peripherin, and phosphodiesterase (Kuhn and Dreyer, 1972;Lee et al, 1984;Boesze-Battaglia et al, 1997;Roof et al, 1997;Hayashi et al, 2000;Hu et al, 2001;Rajala et al, 2002;Trojan et al, 2003). Phosphorylation of Ca 2ϩ -binding proteins, including CaM, can affect their Ca 2ϩ -binding capability and interaction with target proteins (Benaim and Villalobo, 2002). Casein kinase 2 (CK2) phosphorylates several amino acid residues in CaM, including serine 101, which decreases the affinity of CaM for its substrates (Quadroni et al, 1998;Bildl et al, 2004;Kasri et al, 2004;Allen et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Phosphorylation of the Ca²⁺-Binding Protein CaBP4 by Protein Kinase C ζ in Photoreceptors

et al. 2007

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CaBP4 is a calmodulin-like neuronal calcium-binding protein that is crucial for the development and/or maintenance of the cone and rod photoreceptor synapse. Previously, we showed that CaBP4 directly regulates Ca v 1 L-type Ca 2ϩ channels, which are essential for normal photoreceptor synaptic transmission. Here, we show that the function of CaBP4 is regulated by phosphorylation. CaBP4 is phosphorylated by protein kinase C (PKC) at serine 37 both in vitro and in the retina and colocalizes with PKC in photoreceptors. CaBP4 phosphorylation is greater in light-adapted than dark-adapted mouse retinas. In electrophysiological recordings of cells transfected with Ca v 1.3 and CaBP4, mutation of the serine 37 to alanine abolished the effect of CaBP4 in prolonging the Ca 2ϩ current through

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Phosphorylation of calmodulin

Cited by 134 publications

References 79 publications

Calmodulin phosphorylation and modulation of endothelial nitric oxide synthase catalysis

Calmodulin phosphorylation and modulation of endothelial nitric oxide synthase catalysis

Genetic polymorphism and protein conformational plasticity in the calmodulin superfamily: Two ways to promote multifunctionality

Phosphorylation of the Ca²⁺-Binding Protein CaBP4 by Protein Kinase C ζ in Photoreceptors

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Phosphorylation of calmodulin

Cited by 134 publications

References 79 publications

Calmodulin phosphorylation and modulation of endothelial nitric oxide synthase catalysis

Calmodulin phosphorylation and modulation of endothelial nitric oxide synthase catalysis

Genetic polymorphism and protein conformational plasticity in the calmodulin superfamily: Two ways to promote multifunctionality

Phosphorylation of the Ca2+-Binding Protein CaBP4 by Protein Kinase C ζ in Photoreceptors

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Phosphorylation of the Ca²⁺-Binding Protein CaBP4 by Protein Kinase C ζ in Photoreceptors