Phosphorylation of ribosomal protein S6 and its regulation during differentiation of human leukemic cells
Journal of Korean Medical Science
;
: 413-419, 1993.
Article
in English
| WPRIM
| ID: wpr-89027
ABSTRACT
We attempted to study the role of protein tyrosine kinase (PTK) and protein kinase C (PKC) in the cascade of phosphorylation of ribosomal protein S6 during differentiation of leukemic cells (HL-60, THP-1, and RWLeu-4). Neither activation nor inhibition of colony stimulating factor-1 (CSF-1) receptor's PTK activity with CSF-1 or genistein respectively affected the phosphorylation of S6. However, vanadate which is a protein tyrosine phosphatase (PTP) inhibitor showed enhancement of S6 phosphorylation. Dimethylsulfoxide which does not affect either PTK or PKC demonstrated no change in S6 phosphorylation. PKC activation by acute 12-0-tetradecanoyl phorbol-13-acetate (TPA) treatment induced monocytic differentiation and S6 phosphorylation. Surprisingly, the more prominent phosphorylation of S6 protein was observed in PKC-depleted cells by prolonged TPA treatment. Our results suggest that PTK/PTP play a lesser role in S6 phosphorylation of HL-60 cells than PKC does. In addition, two different mechanisms seem to be involved in TPA-induced S6 phosphorylation during HL-60 differentiation PKC activation by acute TPA treatment and PKC depletion which may lead to the synthesis of some endogenous protein responsible for the differentiation by chronic TPA treatment.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Phosphorylation
/
Ribosomal Proteins
/
Protein Kinase C
/
Protein-Tyrosine Kinases
/
Tetradecanoylphorbol Acetate
/
Tumor Cells, Cultured
/
Leukemia
/
Cell Differentiation
/
Macrophage Colony-Stimulating Factor
/
Ribosomal Protein S6
Limits:
Humans
Language:
English
Journal:
Journal of Korean Medical Science
Year:
1993
Type:
Article
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