An improved purification procedure and properties of casein kinase II from brain

Alcázar, Alberto; Martín, M. Elena; López-Fando, Juan; Salinas, Matilde

doi:10.1007/bf00970750

Cited by 22 publications

(17 citation statements)

References 28 publications

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“…CK2-mediated phosphorylation has also been shown to modulate the degradation (either enhancing or decreasing it) of many proteins, including IkB (Schwarz et al, 1996), PTEN (Torres and Pulido, 2001), lens connexin (Yin et al, 2000), chromatin-associated protein HMG1 (Wisniewski et al, 1999), and several transcription factors such as HMGB (Stemmer et al, 2002), Myf-5 (Winter et al, 1997), and c-Myc (Channavajhala and Seldin, 2002). CK2 is most abundant in brain (Alcazar et al, 1988;Girault et al, 1990), and its activity has been implicated in many aspects of brain function, including neuronal survival (Boehning et al, 2003), differentiation (Nuthall et al, 2004), ion channel function (Jones and Yakel, 2003;Bildl et al, 2004), and long-term potentiation and neuronal plasticity (Diaz-Nido et al, 1992;Lieberman and Mody, 1999;Reikhardt et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

Regulation of ΔFosB Stability by Phosphorylation

Ulery¹,

Rudenko²,

Nestler³

2006

J. Neurosci.

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The transcription factor ⌬FosB (also referred to as FosB2 or FosB[short form]) is an important mediator of the long-term plasticity induced in brain by chronic exposure to several types of psychoactive stimuli, including drugs of abuse, stress, and electroconvulsive seizures. A distinct feature of ⌬FosB is that, once induced, it persists in brain for relatively long periods of time in the absence of further stimulation. The mechanisms underlying this apparent stability, however, have remained unknown. Here, we demonstrate that ⌬FosB is a relatively stable transcription factor, with a half-life of ϳ10 h in cell culture. Furthermore, we show that ⌬FosB is a phosphoprotein in brain and that phosphorylation of a highly conserved serine residue (Ser27) in ⌬FosB protects it from proteasomal degradation. We provide several lines of evidence suggesting that this phosphorylation is mediated by casein kinase 2. These findings constitute the first evidence that ⌬FosB is phosphorylated and demonstrate that phosphorylation contributes to its stability, which is at the core of its ability to mediate long-lasting adaptations in brain.

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Section: Discussionmentioning

confidence: 99%

Regulation of ΔFosB Stability by Phosphorylation

Ulery¹,

Rudenko²,

Nestler³

2006

J. Neurosci.

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“…32 P]ATP were supplied by Amersham Biosciences, and synthetic peptides were supplied by Mimotopes. eIF2 and eIF2B were purified from calf brain (38).…”

Section: Methodsmentioning

confidence: 99%

Initiation Factor 2B Activity Is Regulated by Protein Phosphatase 1, Which Is Activated by the Mitogen-activated Protein Kinase-dependent Pathway in Insulin-like Growth Factor 1-stimulated Neuronal Cells

Quevedo

Salinas

Alcázar

2003

Journal of Biological Chemistry

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We have previously demonstrated that insulin-like growth factor 1 (IGF1) induces eukaryotic initiation factor 2B (eIF2B) activation in neuronal cells through the phosphatidylinositol 3 kinase/glycogen synthase kinase 3 pathway as well as by activation of the mitogen-activated protein kinase (MAPK)-activating kinase (MEK)/ MAPK signaling pathway (Quevedo, C., Alcá zar, A., and Salinas, M. (2000) J. Biol. Chem. 275, 19192-19197). This paper addresses the mechanism involved in IGF1-induced eIF2B activation via the MEK/MAPK cascade in cultured neurons treated with IGF1 and demonstrates that extracellular signal-regulated MAP kinase 1 and 2 (ERK1 and -2) immunoprecipitates of IGF1-treated neuronal cells promote this activation. This effect did not directly result from eIF2B phosphorylation by ERK immunoprecipitates. In addition, recombinant ERK1 and -2 neither activate eIF2B nor phosphorylate it. Endogenous protein phosphatase 1 and 2A catalytic subunits (PP1C and PP2AC, respectively) were co-immunoprecipitated with ERK1 and -2, and the association of ERK with PP1C was stimulated by IGF1 treatment, resulting in increased PP1 activity. ERK immunoprecipitates incubated with PP1 inhibitors did not activate eIF2B, indicating that PP1C activates eIF2B. In vitro experiments with phosphorylated eIF2B showed that recombinant PP1C (␣ isoform) dephosphorylates and activates eIF2B. Paralleling eIF2B activation, IGF1 treatment induced PP1 activation in a MEK/MAPK-dependent fashion. Moreover, the treatment of neurons with the PP1 inhibitor tautomycin inhibited PP1 activation and prevented IGF1-induced eIF2B activation. These findings strongly suggest that IGF1-induced eIF2B activation in neurons is effected by PP1, the activation of which is mediated by the MEK/MAPK signaling pathway.The pathway through which growth factors promote their effects in protein synthesis is not fully understood at least in neurons of the central nervous system. Protein synthesis is activated in different cell types by a variety of growth factors essential to cell growth, differentiation, and survival. Translational control starts at the level of initiation (1, 2) and depends on eukaryotic initiation factor 2 (eIF2).1 This binds to GTP and interacts with the initiator methionyl-tRNA (Met-tRNA i ) to form the ternary complex eIF2⅐GTP⅐Met-tRNA i . In this way, eIF2 factor recruits Met-tRNA i to the 40 S ribosomal subunit. This together with other initiation factors binds to mRNA, leading to the recognition of the AUG start codon (3-5). Upon formation of the 80 S initiation complex, GTP is hydrolyzed, and eIF2 is released from the ribosome as a functionally inactive binary complex (eIF2⅐GDP). Eukaryotic initiation factor 2B (eIF2B) is a heteropentameric protein that catalyzes the exchange of bound GDP from eIF2⅐GDP for GTP (4, 6, 7). The eIF2⅐GTP form is then available to undergo further interaction with Met-tRNA i , leading to a new round of initiation. eIF2B activity therefore plays a key role in regulating translation initiation. elF2B factor can be ma...

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“…Synthetic peptides were supplied by Chiron Technologies, anti-GSK-3␤ was from Transduction Laboratories, and anti-phospho-GSK-3␤(Ser 9 ) was supplied by Chemicon. eIF-2 and eIF-2B were purified from calf brain (34).…”

Section: Methodsmentioning

confidence: 99%

Two Different Signal Transduction Pathways Are Implicated in the Regulation of Initiation Factor 2B Activity in Insulin-like Growth Factor-1-stimulated Neuronal Cells

Quevedo¹,

Alcázar²,

Salinas

2000

Journal of Biological Chemistry

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Eukaryotic initiation factor eIF-2B plays an important role in translation regulation and has been suggested to be implicated in the increased protein synthesis promoted in response to growth factors. We have used primary cultured neurons to delineate the signaling pathways by which insulin-like growth factor-1 (IGF-1), which plays a critical role in the survival of neuronal cells, promotes eIF-2B and protein synthesis activation. Treatment of cortical neurons with IGF-1 (100 ng/ml) for 30 min stimulates [ 3 H]methionine incorporation, and a parallel increase in eIF-2B activity was observed. Wortmannin and LY294002 reversed both effects, indicating that phosphatidylinositol 3-kinase mediates IGF-1-induced protein synthesis and eIF-2B activation. IGF-1 induced glycogen synthase kinase-3 (GSK-3) inactivation in a phosphatidylinositol 3-kinasedependent fashion because it is inhibited by wortmannin and LY294002. By using GSK-3 immunoprecipitated from untreated and IGF-1-treated cells, we demonstrate the phosphorylation of eIF-2B coincident with its inactivation. The treatment of cortical neurons with IGF-1 also promoted the activation of mitogen-activated protein kinase (MAPK). The MAPK-activating kinase (MEK) inhibitor PD98059 inhibited MAPK activation and reversed IGF-1-induced protein synthesis and eIF-2B activation. These findings suggest that IGF-1-induced eIF-2B activation on neurons is promoted through phosphatidylinositol 3-kinase and GSK-3 kinase, and we report an IGF-1-induced MEK/MAPK activation pathway implicated in eIF-2B activation.

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An improved purification procedure and properties of casein kinase II from brain

Cited by 22 publications

References 28 publications

Regulation of ΔFosB Stability by Phosphorylation

Regulation of ΔFosB Stability by Phosphorylation

Initiation Factor 2B Activity Is Regulated by Protein Phosphatase 1, Which Is Activated by the Mitogen-activated Protein Kinase-dependent Pathway in Insulin-like Growth Factor 1-stimulated Neuronal Cells

Two Different Signal Transduction Pathways Are Implicated in the Regulation of Initiation Factor 2B Activity in Insulin-like Growth Factor-1-stimulated Neuronal Cells

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