Phosphorylation of the 6-Phosphofructo-2-Kinase/Fructose 2,6-Bisphosphatase/PFKFB3 Family of Glycolytic Regulators in Human Cancer

Abstract

Purpose: Fructose 2,6-bisphosphate (F2,6BP) is a potent activator of phosphofructokinase, which is a rate-limiting enzyme of glycolysis.The concentration of F2,6BP depends on the activity of the bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/ FBPase). Four genes encoding PFK-2/FBPase have been identified and termed PFKFB1 to PFKFB4. PFKFB3 protein is expressed in high levels in human tumors in situ.The purpose of this study was to determine the role of functional interactions between the phosphorylation of PFKFB3 and activated glycolysis in human cancer cells. Experimental Design: cDNA from several human tumor cell lines and human colon carcinoma were analyzed by reverse transcription-PCR to identify different splicing variants of PFKFB3. The effect of phosphorylation of Ser 461 was studied by recombinantly replacing this residue with glutamate (PFKFB3 S461E

Effect of methyl tertial butyl ether on the expression of mRNA coding for 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 and VEGF in rat liver and lung

“…A representative (of four) gel electro phoresis is shown ine residues, however its significance in the regulation of PFKFB-3 activity via phosphory lation has not been studied yet. There are data that phosphorylation of Ser 490 is responsible for activation of glycolysis in human cancer [18]. As shown in Fig.…”

“…5, different alternative splice variants of PFKFB3 mRNA have diffe rent quantity and position of serine residues (underlined) in the Cterminus that could have certain significance in regulation of enzymatic activity through serine phosphorylation [11,18]. Moreover, three bigger splice variants of PFKFB3 mRNA (NM_057135, D87241 and D87242) contain an additional exon 13a (29 amino acid segment), which has six ser Fig.…”

“…PFKFB has two dis tinct catalytic sites on each subunits, one for the 6phosphofructo2kinase activity and the other for the fructose2,6bisphosphatase activity [11,13,16,17]. PFKFB is a key enzyme in the regulation of glycolysis in malignant tumors [17][18][19][20][21].…”

SNF1/AMP-Activated Protein Kinases: Genes, Expression and Biological Role

“…Hypoxia also induces expression of PFKFB-3 in different mouse organs in vivo, except skeletal muscle [42]. High expression level and phosphorylation status of PFKFB-3 as an important glycolytic regulator was determined in different malignant tumours [43][44][45][46][47]. Because SNARK deficiency contributed to the early phase of tumourigenesis and is important in cancer development and tumour progression [13,14], investigation of the expression of PFKFB-3 and its alternative splice variants, which have different proliferative properties [48], is necessary for understanding the role of SNARK deficiency in tumourigenesis.…”

“…3 and 4), supporting the idea that this terminus of the various enzyme isoforms serve to adapt the kinetic properties of the catalytic core to metabolic exigencies of a particular tissue. Alternative splice variants of PFKFB-3 also have different amounts and sequence positions of serine residues which are very important in the regulation of isozyme activity via phosphorylation [39,46]. It was shown that the pattern of alternative splice variants of the PFKFB-3 mRNA differs in different mouse organs (Fig.…”