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Effects of insulin and actin on phosphofructokinase activity and cellular distribution in skeletal muscle

2004; Brazilian Academy of Sciences; Volume: 76; Issue: 3 Linguagem: Inglês

10.1590/s0001-37652004000300008

1678-2690

Ana Paula P. Silva, Gutemberg Gomes Alves, Alexandre Herculano Borges Araújo, Mauro Sola‐Penna,

Adipose Tissue and Metabolism

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 phos-phofructokinase 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.