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			PubMed Journals: EMBO J

  Source:		PMID: 12853467


    		EMBO J. 2003 Jul 15;22(14):3514-23.
     
			14-3-3s regulate fructose-2,6-bisphosphate
			levels by binding to PKB-phosphorylated
			cardiac fructose-2,6-bisphosphate
			kinase/phosphatase.

			Pozuelo Rubio M(1), Peggie M, Wong BH, Morrice
			N, MacKintosh C.

			Author Information
			(1) MRC Protein Phosphorylation Unit, School
			of Life Sciences, University of Dundee,
			Dundee DD1 5EH, Scotland, UK.
			m.pozuelorubio@dundee.ac.uk

			The cardiac isoform of 6-phosphofructo-2-kinase/
			fructose-2,6-bisphosphatase (PFK-2), regulator
			of the glycolysis-stimulating
			fructose-2,6-bisphosphate, was among human
			HeLa cell proteins that were eluted from
			a 14-3-3 affinity column using the phosphopeptide
			ARAApSAPA. Tryptic mass fingerprinting and
			phospho-specific antibodies showed that
			Ser466 and Ser483 of 14-3-3-affinity-purified
			PFK-2 were phosphorylated. 14-3-3 binding
			was abolished by selectively dephosphorylating
			Ser483, and 14-3-3 binding was restored
			when both Ser466 and Ser483 were phosphorylated
			with PKB, but not when Ser466 alone was
			phosphorylated by AMPK. Furthermore, the
			phosphopeptide RNYpS(483)VGS blocked binding
			of PFK-2 to 14-3-3s. These data indicate
			that 14-3-3s bind to phosphorylated Ser483.
			When HeLa cells expressing HA-tagged PFK-2
			were co-transfected with active PKB or stimulated
			with IGF-1, HA-PFK-2 was phosphorylated
			and bound to 14-3-3s. The response to IGF-1
			was abolished by PI 3-kinase inhibitors.
			In addition, IGF-1 promoted the binding
			of endogenous PFK-2 to 14-3-3s. When cells
			were transduced with penetratin-linked AARAApSAPA,
			we found that this reagent bound specifically
			to 14-3-3s, blocked the IGF-1-induced binding
			of HA-PFK-2 to 14-3-3s, and completely inhibited
			the IGF-1-induced increase in cellular
			fructose-2,6-bisphosphate. These findings
			suggest that PKB-dependent binding of 14-3-3s
			to phospho-Ser483 of cardiac PFK-2 mediates
			the stimulation of glycolysis by growth
			factor.

			DOI: 10.1093/emboj/cdg363 PMCID: PMC165633
			PMID: 12853467 [Indexed for MEDLINE]

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