Abstract
The aim of the present work was to attempt to partially purify PA28 (REG) α and γ (Ki antigen) in the nuclear fraction from NT2/D1 cells. Nuclei were isolated by the hypertonic sucrose gradient centrifugation method and fractionated into membrane/nucleoplasmic and chromatin/nucleolar fractions. Western blotting with anti-histone and anti-β-tubulin monoclonal antibodies confirmed the accuracy of the procedure. Proteasomes were present mainly in the cytoplasm but also in the nuclei. Disruption of the nuclear envelope released the proteasomes implying a loose or no binding with the chromatin. PA28α and γ were detected mainly in the cytosol and to a lesser extent in the crude nuclear pellet, however the purified nuclei were devoid of PA28α and γ. This indicates, that only a small fraction of the PA28 activator is present in the nuclei as detected by immunofluorescence or/and it is easily removed during nuclear purification.
Original language | English (US) |
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Pages (from-to) | 273-276 |
Number of pages | 4 |
Journal | International Journal of Biochemistry and Cell Biology |
Volume | 31 |
Issue number | 2 |
DOIs | |
State | Published - Feb 1999 |
Externally published | Yes |
Keywords
- NT2 cells
- Nucleus
- PA28
- Proteasome
- Proteasome activator
ASJC Scopus subject areas
- Biochemistry
- Cell Biology