ISSN:
1573-4919
Keywords:
fructose 2,6-bisphosphate
;
6-phosphofructo-2-kinase
;
K562 cell differentiation
;
MEG-01 cell differentiation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
Notes:
Abstract Fructose 2,6-bisphosphate (Fru-2,6-P2) represents the most powerful activator of 6-phosphofructo-l-kinase, rate-limiting enzyme of glycolysis. Fru-2,6-P2 content is tightly regulated and appears to be under the control of different hormones and growth factors, acting either through covalent modification of isoenzymatic forms of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase (PFK-2/FBPase-2), the bifunctional enzyme responsible for the synthesis and the degradation of the compound, or through changes in transcription rate and/or in the expression of different isoforms of the enzyme. In the present study the metabolism of Fru-2,6-P2 was investigated during the differentiation toward megakaryocytes induced by phorbol 12-myristate 13-acetate (PMA) treatment of human leukemia K562 and MEG-O1 cell lines. Fru-2,6-P2 content as well as PFK-2 activity were increased in a dose-dependent manner after 4 days of incubation with PMA. MEG-01 cells resulted more sensitive to the effect of the inducer, anyway in both cell types cytostatic concentrations of the phorbol ester were able to affect Fru-2,6-P2 metabolism. The effect of PMA was maximal at 4 days of incubation in both examined cell lines. Interestingly, the effect induced by the phorbol ester at 4 days was still appreciable subculturing K562 and MEG-01 cells for 3 days in the absence of the inducer and was associated with relevant changes in the molecular properties of PFK-2: namely increased Vmax and Km. This latter finding suggests that the rise in Fru-2,6-P2 content during the differentiation process toward megakaryocytes might result from the expression of a novel PFK-2 isoform.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00426334
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