Interaction of Protein Phosphatase 1δ with Nucleophosmin in Human Osteoblastic Cells
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- Haneji Tatsuji
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School
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- Teramachi Jumpei
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School
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- Hirashima Kanji
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School
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- Kimura Koji
- Department of Histology and Oral Histology, Institute of Health Biosciences, The University of Tokushima Graduate School
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- Morimoto Hiroyuki
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health
Bibliographic Information
- Other Title
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- Interaction of protein phosphatase 1delta with nucleophosmin in human osteoblastic cells
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Abstract
Protein phosphorylation and dephosphorylation has been recognized as an essential mechanism in the regulation of cellular metabolism and function in various tissues. Serine and threonine protein phosphatases (PP) are divided into four categories: PP1, PP2A, PP2B, and PP2C. At least four isoforms of PP1 catalytic subunit in rat, PP1α, PP1γ1, PP1γ2, and PP1δ, were isolated. In the present study, we examined the localization and expression of PP1δ in human osteoblastic Saos-2 cells. Anti-PP1δ antibody recognized a protein present in the nucleolar regions in Saos-2 cells. Cellular fractionation revealed that PP1δ is a 37 kDa protein localized in the nucleolus. Nucleophosmin is a nucleolar phosphoprotein and located mainly in the nucleolus. Staining pattern of nucleophosmin in Saos-2 cells was similar to that of PP1δ. PP1δ and nucleophosmin were specifically stained as dots in the nucleus. Dual fluorescence images revealed that PP1δ and nucleophosmin were localized in the same regions in the nucleolus. Similar distribution patterns of PP1δ and nucleophosmin were observed in osteoblastic MG63 cells. The interaction of PP1δ and nucleophosmin was also shown by immunoprecipitation and Western analysis. These results indicated that PP1δ associate with nucleophosmin directly in the nucleolus and suggested that nucleophosmin is one of the candidate substrate for PP1δ.<br>
Journal
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- ACTA HISTOCHEMICA ET CYTOCHEMICA
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ACTA HISTOCHEMICA ET CYTOCHEMICA 45 (1), 1-7, 2012
JAPAN SOCIETY OF HISTOCHEMISTRY AND CYTOCHEMISTRY