title: Effects of insulin and actin on phosphofructokinase activity and cellular distribution in skeletal muscle.
abstract: In this work, we report evidences that the association of phosphofructokinase and F-actin can be affected by insulin stimulation in rabbit skeletal muscle homogenates and that this association can be a mechanism of phosphofructokinase regulation. Through co-sedimentation techniques, we observed that on insulin-stimulated tissues, approximately 70% of phosphofructokinase activity is co-located in an actin-enriched fraction, against 28% in control. This phenomenon is accompanied by a 100% increase in specific phosphofructokinase activity in stimulated homogenates. Purified F-actin causes an increase of 230% in phosphofructokinase activity and alters its kinetic parameters. The presence of F-actin increases the affinity of phosphofructokinase for fructose 6-phosphate nevertheless, with no changes in maximum velocity (Vmax). Here we propose that the modulation of cellular distribution of phosphofructokinase may be one of the mechanisms of control of glycolytic flux in mammalian muscle by insulin.
authors.affiliation: Laboratório de Enzimologia e Controle do Metabolismo, Departamento de Fármacos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-590, Brasil.
authors.forename: Ana Paula P
authors.initials: AP
authors.lastname: Silva
authors.forename: Gutemberg G
authors.initials: GG
authors.lastname: Alves
authors.forename: Alexandre H B
authors.initials: AH
authors.lastname: Araújo
authors.forename: Mauro
authors.initials: M
authors.lastname: Sola-Penna
mesh_terms: D000199:Actins / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D006019:Glycolysis; D007328:Insulin / Q000494:pharmacology*; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000187:drug effects / Q000201:enzymology*; D025221:Phosphofructokinases / Q000187:drug effects* / Q000502:physiology; D011817:Rabbits
chemical_list: D000199:Actins; D007328:Insulin; D025221:Phosphofructokinases; D005947:Glucose