Subcellular Localization of Protein Phosphatase Type 1 Isotypes in Mouse Osteoblastic Cells

Haneji, Tatsuji; Morimoto, Hiroyuki; Morimoto, Yasuhiro; Shirakawa, Satoko; Kobayashi, Shigeru; Kaneda, Chihiro; Shima, Hiroshi; Nagao, Minako

doi:10.1006/bbrc.1998.8913

Cited by 20 publications

(15 citation statements)

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“…Very little of the immunoreactive proteins were detected in the cytosolic fraction. PP1a antibody recognized proteins with an estimated molecular weight of 38 kDa present in the nucleus, whereas PP1g1 interacted with the 36 kDa proteins in cytoplasm [20]. The estimated molecular weight of the interacted proteins is in good agreement with that calculated from the amino acid sequences [55,57].…”

Section: Subcellular Localization Of Pp1 Isozymessupporting

confidence: 71%

“…1B). The nucleoluslocalization of PP1d was further confirmed by the fact that the PP1d antibody recognized the proteins present preferentially in nucleolar fraction [20]. The punctuated distribution of PP1g1 in cytoplasm was especially distinct in the perinuclear region (Fig.…”

Section: Subcellular Localization Of Pp1 Isozymesmentioning

confidence: 58%

“…We examined the subcellular localization of PP1 isotypes in mouse osteoblastic MC3T3-E1 cells [20]. Figure 1 shows the distribution of PP1s in murine osteoblastic MC3T3-E1 cells.…”

Section: Subcellular Localization Of Pp1 Isozymesmentioning

confidence: 99%

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Association of Protein Phosphatase 1 Delta with Nucleolin in Osteoblastic Cells and Cleavage of Nucleolin in Apoptosis-induced Osteoblastic Cells

Haneji

2005

Acta Histochem. Cytochem

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Protein phosphorylation and dephosphorylation has been recognized as a key mechanism in cell function. Okadaic acid is a potent inhibitor of PP1 and PP 2A and induces apoptosis in human or mouse cells including osteoblasts. Nucleolin is an abundantly expressed nucleolar phosphoprotein and is located mainly in the nucleolus. The staining pattern of nucleolin in cultured osteoblastic cells is similar to that of PP1d. Nucleolin was demonstrated to bind to PP1d in nucleolus in human osteoblastic cells by using immunocytochemical and immunoprecipitation methods. AgNORs and nucleolin, visible as dots in the nuclei of the control osteoblastic cells, disappeared from the nuclei of the osteoblastic cells treated with okadaic acid. A major band, 110 kDa, was detected in the proteins obtained from osteoblastic cells. The level of the 110 kDa protein decreased in the apoptotic osteoblastic cells, whereas an additional band, 80 kDa, appeared and the level of this protein increased in the proteins prepared from okadaic acid-induced apoptotic osteoblastic cells. Our results indicate that PP1d directly binds to nucleolin in the nucleolus of osteoblastic cells and that nucleolin is cleaved during apoptosis in osteoblastic cells.

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Section: Subcellular Localization Of Pp1 Isozymessupporting

confidence: 71%

Section: Subcellular Localization Of Pp1 Isozymesmentioning

confidence: 58%

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Association of Protein Phosphatase 1 Delta with Nucleolin in Osteoblastic Cells and Cleavage of Nucleolin in Apoptosis-induced Osteoblastic Cells

Haneji

2005

Acta Histochem. Cytochem

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“…In a previous study, we showed the subcellular localization of PP1 isoforms in mouse osteoblastic cells. 9 The function of PP1s depends on the localization of these enzymes in the cells, because, like protein kinases, PP should be associated with or located near their substrates. It was previously shown that nucleolin and PP1 were associated with each other and co-localized in the nucleolus in MG63 cells.…”

Section: Discussionmentioning

confidence: 99%

“…8 In a previous study, we reported the subcellular localization of PP1 isoforms in mouse osteoblastic MC3T3-E1 cells. 9 PP1 targeting subunits are thought to direct PP1 to specific subcellular components where the enzymes act at these sites. Nucleolin is an abundantly expressed phosphoprotein located mainly in the nucleolus.…”

Section: Introductionmentioning

confidence: 99%

Differential expression of protein phosphatase type 1 isotypes and nucleolin during cell cycle arrest

Morimoto

Ozaki

Okamura

et al. 2005

Cell Biochemistry & Function

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In the present study, we examined the expression and cytolocalization of protein phosphatase type 1 (PP1) isoforms and nucleolin in human osteoblastic cell line MG63 cells at two boundaries in the cell cycle. We treated MG63 cells with hydroxyurea and nocodazole to arrest the cells at the G(1)/S and G(2)/M boundaries, respectively. As judged from the results of Western blot analysis, PP1 isoforms were expressed differently at each boundary of the cell cycle. Nucleolin was also shown to have a different expression pattern at each boundary. In the hydroxyurea-treated cells, nucleolus-like bodies were bigger in size and decreased in number compared with those in asynchronized cells. However, the subcellular localization of PP1s and nucleolin was not changed. Anti-nucleolin antibody interacted with 110-kDa and 95-kDa proteins present in asynchronized cells and in the cells treated with hydroxyurea. Treatment of the cells with nocodazole decreased the level of the 95-kDa form of nucleolin. In the nocodazole-treated cells, it was impossible to distinguish the distribution of each protein. The phosphorylation status of nucleolin in the cell cycle arrested samples was examined by 2D-IEF-PAGE followed by Western blot analysis. In the case of asynchronized cells or hydroxyurea-treated ones, nucleolin was located at a basic isoelectric point (dephosphorylated status); whereas in the G(2)/M arrest cells, the isoelectric point of nucleolin shifted to an acidic status, indicating that nucleolin was phosphorylated. The present results indicate that PP1 and nucleolin were differently expressed at G(1)/S and G(2)/M boundaries of the cell cycle and acted in a different fashion during cell-cycle progression.

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Distribution of protein phosphatases‐1α and ‐1γ1 and the D₁ dopamine receptor in primate prefrontal cortex: Evidence for discrete populations of spines

Muly

Greengard

Goldman‐Rakic

2001

J of Comparative Neurology

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The function of G protein-coupled receptors depends on the availability of the appropriate signal transduction proteins in close proximity to the receptor. We have examined and quantified in primate prefrontal cortex the subcellular distribution of two isoforms of protein phosphatase-1 (PP1), PP1 alpha and PP1 gamma 1, which are components of the signal transduction pathway accessed by the D(1) dopamine receptor. Both PP1 alpha- and PP1 gamma 1-labeled puncta are seen in cortex, basal ganglia, hippocampus, and thalamus. Viewed with the electron microscope, both PP1 isoforms are selectively localized to dendritic spines and are found in different percentages of spines; PP1 alpha is present in roughly 70% and PP1 gamma 1 in roughly 40% of dendritic spines. Our analysis indicates that three populations of spines are defined by the distribution of these PP1 isoforms: those that contain both PP1 alpha and PP1 gamma 1, those that contain only PP1 alpha and those that contain neither. The D(1) receptor is present in a subset of the population that contains both PP1 alpha and PP1 gamma 1. The nonhomogeneous distribution of signal transduction proteins in the spines and dendrites of cortical pyramidal cells may help to explain differences in the actions of receptors that nominally use the same signal-transduction pathway.

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Subcellular Localization of Protein Phosphatase Type 1 Isotypes in Mouse Osteoblastic Cells

Cited by 20 publications

References 25 publications

Association of Protein Phosphatase 1 Delta with Nucleolin in Osteoblastic Cells and Cleavage of Nucleolin in Apoptosis-induced Osteoblastic Cells

Association of Protein Phosphatase 1 Delta with Nucleolin in Osteoblastic Cells and Cleavage of Nucleolin in Apoptosis-induced Osteoblastic Cells

Differential expression of protein phosphatase type 1 isotypes and nucleolin during cell cycle arrest

Distribution of protein phosphatases‐1α and ‐1γ1 and the D₁ dopamine receptor in primate prefrontal cortex: Evidence for discrete populations of spines

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Subcellular Localization of Protein Phosphatase Type 1 Isotypes in Mouse Osteoblastic Cells

Cited by 20 publications

References 25 publications

Association of Protein Phosphatase 1 Delta with Nucleolin in Osteoblastic Cells and Cleavage of Nucleolin in Apoptosis-induced Osteoblastic Cells

Association of Protein Phosphatase 1 Delta with Nucleolin in Osteoblastic Cells and Cleavage of Nucleolin in Apoptosis-induced Osteoblastic Cells

Differential expression of protein phosphatase type 1 isotypes and nucleolin during cell cycle arrest

Distribution of protein phosphatases‐1α and ‐1γ1 and the D1 dopamine receptor in primate prefrontal cortex: Evidence for discrete populations of spines

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Product

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Distribution of protein phosphatases‐1α and ‐1γ1 and the D₁ dopamine receptor in primate prefrontal cortex: Evidence for discrete populations of spines