Differential expression of protein phosphatase 1 isoforms in mammalian brain

Silva, EF da Cruz e; Fox, Charles A.; Ouimet, Charles C.; Gustafson, Eric L.; Watson, SJ; Greengard, Paul

doi:10.1523/jneurosci.15-05-03375.1995

Cited by 157 publications

(107 citation statements)

References 22 publications

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“…The following antibodies were used for immunoblotting at appropriate concentrations as recommended by the manufacturer: anti-p35 and anti-cdk5 rabbit polyclonal antibodies (C-19 and C-8; Santa Cruz Biotechnology, Santa Cruz, CA), anti-human Tau mouse monoclonal antibody HT-7 (MN1000; Pierce Biotechnology, Rockford, IL), anti-RD3 (Upstate USA, Charlottesville, VA), anti-PKA (Cell Signaling Technology, Beverly, MA), anti-PP2A-A (SC-6112; Santa Cruz Biotechnology), CK-1 (2655; Cell Signaling Technology), CK-2 (2656; Cell Signaling Technology), anti-Hsp90 (SC-7947; Santa Cruz Biotechnology), anti-Hsp70 mouse monoclonal antibody (SPA-810; Stressgen Bioreagents, Victoria, BC, Canada), anti-C terminus of heat-shock cognate 70-interacting protein rabbit polyclonal antibody (PC711; Calbiochem, Darmstadt, Germany), and anti-␤-actin mouse monoclonal antibody (A1978; Sigma, St. Louis, MO). Antibodies against PP-1␣ and PP-1␥ were generated as reported previously (42). Antibodies recognizing phosphorspecific epitopes on Tau, AT8 for S202/T205, AT180 for T231, and AT270 for T181, were purchased from Pierce Biotechnology.…”

Section: Methodsmentioning

confidence: 99%

Roles of heat-shock protein 90 in maintaining and facilitating the neurodegenerative phenotype in tauopathies

Luo

Dou

Rodina

et al. 2007

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

256

226

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Neurodegeneration, a result of multiple dysregulatory events, is a lengthy multistep process manifested by accrual of mutant variants and abnormal expression, posttranslational modification, and processing of certain proteins. Accumulation of these dysregulated processes requires a mechanism that maintains their functional stability and allows the evolution of the neurodegenerative phenotype. In malignant cells, the capacity to buffer transformation has been attributed to heat-shock protein 90 (Hsp90). Although normal proteins seem to require limited assistance from the chaperone, their aberrant counterparts seem to be highly dependent on Hsp90. Whereas enhanced Hsp90 affinity for mutated or functionally deregulated client proteins has been observed for several oncoproteins, it is unknown whether Hsp90 plays a similar role for neuronal proteins and thus maintains and facilitates the transformed phenotype in neurodegenerative diseases. Tauopathies are neurodegenerative diseases characterized by aberrant phosphorylation and/or expression of Tau protein, leading to a timedependent accumulation of Tau aggregates and subsequent neuronal death. Here, we show that the stability of p35, a neuronal protein that activates cyclin-dependent protein kinase 5 through complex formation leading to aberrant Tau phosphorylation, and that of mutant but not WT Tau protein is maintained in tauopathies by Hsp90. Inhibition of Hsp90 in cellular and mouse models of tauopathies leads to a reduction of the pathogenic activity of these proteins and results in elimination of aggregated Tau. The results identify important roles played by Hsp90 in maintaining and facilitating the degenerative phenotype in these diseases and provide a common principle governing cancer and neurodegenerative diseases.cyclin-dependent protein kinase 5 ͉ neurodegeneration ͉ Tau

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Section: Methodsmentioning

confidence: 99%

Roles of heat-shock protein 90 in maintaining and facilitating the neurodegenerative phenotype in tauopathies

Luo

Dou

Rodina

et al. 2007

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

256

226

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“…33), or PKC-(5 l; Sigma-Aldrich). Then 50 l of a 50% (v/v) suspension of protein A-Agarose (Amersham Biosciences) were added, and the mixture was incubated overnight as above.…”

Section: Methodsmentioning

confidence: 99%

Group I Metabotropic Glutamate Receptors Bind to Protein Phosphatase 1C

Croci

Sticht

Brandstätter

et al. 2003

Journal of Biological Chemistry

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The modulation of neurotransmitter receptors by kinases and phosphatases represents a key mechanism in controlling synaptic signal transduction. However, molecular determinants involved in the specific targeting and interactions of these enzymes are largely unknown. Here, we identified both catalytic ␥-isoforms of protein phosphatase 1C (PP1␥1 and PP1␥2) as binding partners of the group I metabotropic glutamate receptors type 1a, 5a, and 5b in yeast cells and pull-down assays, using recombinant and native protein preparations. The tissue distribution of interacting proteins was compared, and protein phosphatase 1C was detected in dendrites of retinal bipolar cells expressing the respective interacting glutamate receptors. We mapped interacting domains within binding partners and identified five amino acids in the intracellular C termini of the metabotropic glutamate receptors type 1a, 5a, 5b, and 7b being both necessary and sufficient to bind protein phosphatase 1C. Furthermore, we show a dose-dependent competition of these C termini in binding the enzyme. Based on our data, we investigated the structure of the identified amino acids bound to protein phosphatase 1C by homology-based molecular modeling. In summary, these results provide a molecular description of the interaction between protein phosphatase 1C and metabotropic glutamate receptors and thereby increase our understanding of glutamatergic signal transduction.The correct targeting and localization of proteins to synaptic specializations represents an important biological mechanism to regulate neuronal excitability. Increasing evidence underlines the importance of macromolecular signaling complexes, where functionally related proteins such as ion channels, neurotransmitters receptors, kinases, and phosphatases are arranged in close vicinity and are physically anchored to the synaptic cytoskeleton. Therefore, identification and characterization of interactions between synaptically localized proteins adds substantially to our understanding of molecular mechanisms of neurotransmission.Receptors for glutamate are divided in ion channel-associated (ionotropic) receptors of the AMPA-, Kainate-, and NMDAtype and in G-protein coupled (metabotropic) receptors. Although ionotropic glutamate receptors mediate fast synaptic transmission, metabotropic glutamate receptors (mGluRs) 1 modulate neuronal excitability and development, synaptic plasticity, transmitter release, and memory function using a variety of intracellular second messenger systems (1). The eight known members of this protein family are sub-divided into three groups, based on sequence homology, associated second messenger systems, and pharmacological properties (2). mGluR1 and mGluR5 (group I) stimulate phospholipase C, are selectively activated by quisqualate, and are generally expressed perisynaptically at postsynaptic sites (3-7). mGluR2 and mGluR3 (group II) are negatively coupled to adenylyl cyclase and do not show a specific preference for pre-or postsynaptic neurons (8 -10). mGluR4, mGluR7, and...

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“…Rabbit polyclonal PP-1C␣ antibody was prepared as described (29). PP-1C␣ phosphorylation-statespecific rabbit antisera, G-97 and G-98, were raised against the chemically phosphorylated synthetic peptide, Gly-Arg-Pro-Ile-(phospho-Thr)-Pro-Pro-Asn (residues 316-323 of PP-1C␣).…”

Section: Methodsmentioning

confidence: 99%

Cell cycle-dependent phosphorylation of mammalian protein phosphatase 1 by cdc2 kinase

Kwon

Lee

Choi

et al. 1997

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

207

192

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Protein phosphatase 1 (PP-1) is known to be a critical component of eukaryotic cell cycle progression. In vitro, our previous studies showed that cdc2 kinase phosphorylates Thr-320 (T320) in PP-1, and that this leads to inhibition of enzyme activity. To examine directly the phosphorylation of PP-1 in intact mammalian cells, an antibody has been prepared that specifically recognizes PP-1C␣ phosphorylated at T320. Cell synchronization studies revealed in a variety of cell types that T320 of PP-1 was phosphorylated to high levels only during early to mid-mitosis. The phosphorylation of T320 of PP-1 was reduced by the cyclin-dependent protein kinase inhibitor, olomoucine, and increased by the PP-1͞PP-2A inhibitor, calyculin A. Immunof luorescence microscopy using phospho-T320 antibody indicated that in NIH 3T3 cells the phosphorylation of PP-1 began to increase from basal levels in prophase and to peak at metaphase. Immunostaining indicated that phospho-PP-1 was localized exclusively to nonchromosomal regions. Furthermore, in cell fractionation studies of mitotic cells, phospho-PP-1 was detectable only in the soluble fraction. These observations suggest that phosphorylation by cdc2 kinase in early to mid-mitosis and inhibition of PP-1 activity is likely to contribute to the increased state of phosphorylation of proteins that is critical to the initiation of normal cell division.Protein phosphorylation is widely recognized as the major mechanism that controls cell cycle progression. A family of cyclin-dependent protein kinases (CDKs) have been identified and found to be enzymes critical for the initiation and completion of DNA replication and cell division from yeast to mammals (1-5). The activity of CDKs is modulated through phosphorylation of their catalytic subunits and by association with activating or inhibiting proteins. For example, mitotic transition is mediated by the cdc2 kinase͞cyclin B complex, and activated cdc2 kinase has been found to drive dramatic structural reorganizations in the nuclear envelope, spindle apparatus, and chromosomal DNA by phosphorylation of a variety of substrates including histone, Eg5, lamin, vimentin, and plectin (6-12).Evidence suggests that serine͞threonine protein phosphatases function as crucial regulators of cell proliferation (4, 13-15). In particular, protein phosphatase 1 (PP-1), which is highly conserved in all eukaryotes, has been found to play a pivotal role in the cell cycle. Genetic studies have indicated that mutation of the enzyme in yeast, Aspergillus, and in Drosophila leads to a variety of defects in mitosis (16-18). Microinjection of anti-PP-1 antibody into B cells before cell division arrests cells at metaphase, whereas injection of PP-1 into anaphase cells accelerates cytokinesis (19). Expression of inhibitor-2, a specific PP-1 inhibitor, changes during the cell cycle, peaking during S phase and mitosis (20). Thus, the tightly balanced activity of CDKs and PP-1 appears to be required for normal cell division. However, the substrates that are targets f...

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Differential expression of protein phosphatase 1 isoforms in mammalian brain

Cited by 157 publications

References 22 publications

Roles of heat-shock protein 90 in maintaining and facilitating the neurodegenerative phenotype in tauopathies

Roles of heat-shock protein 90 in maintaining and facilitating the neurodegenerative phenotype in tauopathies

Group I Metabotropic Glutamate Receptors Bind to Protein Phosphatase 1C

Cell cycle-dependent phosphorylation of mammalian protein phosphatase 1 by cdc2 kinase

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