Serotonin stimulates mouse skeletal muscle 6-phosphofructo-1-kinase through tyrosine-phosphorylation of the enzyme altering its intracellular localization

Mol Genet Metab. 2007 Dec;92(4):364-70. doi: 10.1016/j.ymgme.2007.07.010. Epub 2007 Aug 27.

Abstract

Serotonin (5-HT) is a hormone implicated in the regulation of many physiological and pathological events. One of its most intriguing properties is the ability to up-regulate mitosis. Moreover, it has been shown that 5-HT stimulate glucose uptake on skeletal muscle, suggesting that 5-HT may regulate glucose metabolism of peripheric tissues. Here we demonstrate that 5-HT stimulates skeletal muscle 6-phosphofructo-1-kinase (PFK) activity in a dose-response manner, through 5-HT(2A) receptor subtype. Maximal activation of the enzyme (2.5-fold compared to control) is achieved in the presence of 25pM 5-HT, increasing both PFK maximal velocity and affinity for the substrate fructose-6-phosphate. These effects occur due to tyrosine phosphorylation of the enzyme that is 2-fold enhanced upon 5-HT stimulation of skeletal muscles preparation. Once 5-HT-induced tyrosine phosphorylation of PFK is prevented by genistein, a tyrosine kinase inhibitor, the hormone stimulatory effect on PFK is abrogated. Wortmannin, a phosphatidylinositol-3-kinase (PI3K) inhibitor, does not interfere on 5-HT-induced stimulation of PFK, supporting that the observed effects are independent on insulin signaling pathway. Furthermore, 5-HT promotes the association of PFK to the muscle f-actin, suggesting that the hormone alters PFK intracellular distribution, favoring its association to the cytoskeleton. Altogether, our results support evidences that 5-HT augments skeletal muscle glucose consumption through stimulation of glycolysis key regulatory enzyme, PFK, throughout tyrosine phosphorylation and intracellular redistribution of the enzyme.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Glucose / metabolism*
  • Glycolysis*
  • Mice
  • Muscle, Skeletal / drug effects*
  • Muscle, Skeletal / enzymology
  • Muscle, Skeletal / physiology
  • Phosphofructokinase-1 / antagonists & inhibitors
  • Phosphofructokinase-1 / chemistry
  • Phosphofructokinase-1 / metabolism*
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology
  • Serotonin / pharmacology*
  • Tyrosine / metabolism

Substances

  • Protein Kinase Inhibitors
  • Serotonin
  • Tyrosine
  • Phosphofructokinase-1
  • Glucose