[Selective accumulation of alkaline phosphatase in the microsomes of human cells cultured in the G0-phase of the cell cycle].
The subcellular distribution of alkaline phosphatase in normal and transformed cultivated human cells was investigated. The total activity of alkaline phosphatase in the transformed cells exceeds that in normal cells 10- (or more) fold and is sharply increased with a rise in the cell population density. The proliferating cells have the same specific activity of alkaline phosphatase in the mitochondrial-lysosomal and microsomal fractions. The transition of normal cells to the G0-phase of the cell cycle is accompanied by an increase in the total enzyme activity and selective accumulation of alkaline phosphatase in the microsomes. An addition of exogenous alkaline phosphatase to intact cells leads to the stimulation of DNA synthesis and to changes in cell morphology. The data obtained suggest that alkaline phosphatase can participate in the destabilization of the cytoskeleton and stimulate cell proliferation. However, in normal cells the selective accumulation of the enzyme in the membranes may hamper its biosynthesis. the activity of alkaline phosphatase thus does not reach the level sufficient for unrestricted cell growth.
D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000378:metabolism*; D002453:Cell Cycle; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D006801:Humans; D007399:Interphase / Q000187:drug effects*; D008861:Microsomes / Q000201:enzymology*; D011003:Ploidies; D013347:Subcellular Fractions / Q000201:enzymology
D004247:DNA; D000469:Alkaline Phosphatase
Izbiratel'noe nakoplenie shchelochnoĭ fosfatazy v mikrosomakh kul'tiviruemykh kletok cheloveka v G0-faze kletochnogo tsikla.