Dimer interface rearrangement of the 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase rat liver isoenzyme by cAMP-dependent Ser-32 phosphorylation.
The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2) is a key regulator of carbohydrate metabolism in liver. The goal of this study was to elucidate the regulatory role of Ser-32 phosphorylation on the kinase domain mediated dimerization of PFK-2/FBPase-2. Fluorescence-based mammalian two-hybrid and sensitized emission fluorescence resonance energy transfer analyses in cells revealed preferential binding within homodimers in contrast to heterodimers. Using isolated proteins a close proximity of two PFK-2/FBPase-2 monomers was only detectable in the phosphorylated enzyme dimer. Thus, a flexible kinase interaction mode exists, suggesting dimer conformation mediated coupling of hormonal and posttranslational enzyme regulation to the metabolic response in liver.
Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
Sara
S
Langer
David A
DA
Okar
Julia
J
Schultz
Sigurd
S
Lenzen
Simone
S
Baltrusch
D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002522:Chlorocebus aethiops; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D019281:Dimerization; D031541:Fluorescence Resonance Energy Transfer; D008099:Liver / Q000201:enzymology*; D025481:Phosphofructokinase-2 / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D012694:Serine / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D005576:Colforsin; D012694:Serine; D000242:Cyclic AMP; D025481:Phosphofructokinase-2