Changes of nuclear protein kinase C activity and isotype composition in PC12 cell proliferation and differentiation

Paola Borgatti, Meri Mazzoni, Cinzia Carini, Luca Maria Neri, Marco Marchisio, Lucia Bertolaso, Maurizio Previati, Giorgio Zauli, Silvano Capitani

Research output: Contribution to journalArticle

Abstract

To establish whether protein kinase C was involved in the nuclear events underlying cell differentiation and proliferation, rat pheochromocytoma PC12 cells, serum-starved for 24 h, were treated with either differentiating doses of nerve growth factor or high serum concentrations, which represented a powerful mitogenic stimulus. Western blot analysis with isoform-specific antibodies, performed on whole cell homogenates, cytoplasms, and purified nuclei, showed that PKC isotypes α, βI, βII, δ, ε, η, and ζ were expressed in PC12 cells and that all of them, except for βI, were found at the nuclear level, variably modulated depending on the cell treatment. Compared to serum-stimulated cells, in which an early (1 day) and marked rise of protein kinase C activity was followed by a plateau, nerve growth factor- treated cells showed a progressive increase of protein kinase C activity coincident with the onset and maintenance of the differentiated phenotype. Western blot analysis of nuclei isolated from fully differentiated cells demonstrated an increase of protein kinase C α, paralleled by enhanced phosphotransferase activity along with the nerve growth factor treatment, and complete loss of the δ isotype. In contrast, in nuclei of proliferating PC12 cells, after an early but modest increase at 1 day of mitogenic stimulation, protein kinase C activity reached a plateau. Isotype-specific analysis indicated a concomitant increase of protein kinase C βII, δ, and ζ and the appearance of protein kinase C ε and η at the nuclear level. Considering the relative intensity of the cytoplasmic and nuclear immunoreactive bands under the three conditions examined, clear-cut translocation to the nucleus occurred for PKC ε and η in serum-stimulated cells. Additional nuclear accumulation of PKC by translocation from the cytoplasm was prominently induced for the ζ isoform after mitogenic stimulation and for PKC α during prolonged NGF treatment. Our data suggest that nuclear translocation and selective activation of distinct protein kinase C isoforms play a relevant role in the control of proliferation and differentiation of the same cell type and that nuclear protein kinase C is crucial to the induction and persistence of the differentiated neuronal phenotype of PC12 cells.

Original languageEnglish
Pages (from-to)72-78
Number of pages7
JournalExperimental Cell Research
Volume224
Issue number1
DOIs
Publication statusPublished - Apr 10 1996

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PC12 Cells
Nuclear Proteins
Protein Kinase C
Cell Differentiation
Cell Proliferation
Nerve Growth Factor
Protein Isoforms
Serum
Cytoplasm
Western Blotting
Phenotype
Pheochromocytoma
Phosphotransferases
Maintenance
Antibodies

ASJC Scopus subject areas

  • Cell Biology

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Borgatti, P., Mazzoni, M., Carini, C., Neri, L. M., Marchisio, M., Bertolaso, L., ... Capitani, S. (1996). Changes of nuclear protein kinase C activity and isotype composition in PC12 cell proliferation and differentiation. Experimental Cell Research, 224(1), 72-78. https://doi.org/10.1006/excr.1996.0112

Changes of nuclear protein kinase C activity and isotype composition in PC12 cell proliferation and differentiation. / Borgatti, Paola; Mazzoni, Meri; Carini, Cinzia; Neri, Luca Maria; Marchisio, Marco; Bertolaso, Lucia; Previati, Maurizio; Zauli, Giorgio; Capitani, Silvano.

In: Experimental Cell Research, Vol. 224, No. 1, 10.04.1996, p. 72-78.

Research output: Contribution to journalArticle

Borgatti, P, Mazzoni, M, Carini, C, Neri, LM, Marchisio, M, Bertolaso, L, Previati, M, Zauli, G & Capitani, S 1996, 'Changes of nuclear protein kinase C activity and isotype composition in PC12 cell proliferation and differentiation', Experimental Cell Research, vol. 224, no. 1, pp. 72-78. https://doi.org/10.1006/excr.1996.0112
Borgatti, Paola ; Mazzoni, Meri ; Carini, Cinzia ; Neri, Luca Maria ; Marchisio, Marco ; Bertolaso, Lucia ; Previati, Maurizio ; Zauli, Giorgio ; Capitani, Silvano. / Changes of nuclear protein kinase C activity and isotype composition in PC12 cell proliferation and differentiation. In: Experimental Cell Research. 1996 ; Vol. 224, No. 1. pp. 72-78.
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