Exercise-induced modulation of intracellular signaling pathways.

Intracellular signaling pathways transduce cellular activation, induced by ligand-receptor ligation, into a cellular response like secretion or proliferation. Signaling processes involve either the release/formation of diffusible second messengers or the transfer of phosphate groups. These signaling cascades involve many steps sensitive to exogenous modulation and have been shown to be involved during the pathogenesis of several diseases. Therefore, the investigation of the regulation of cellular signal transduction mechanisms by exercise should be a valuable tool for a better understanding of exercise-induced immunomodulation. Within this review, important signaling pathways and their cross-talk in leukocytes are described. Furthermore, exercise related changes in metabolism, endocrine system, and environmental stress and their possible influence on intracellular signaling steps are discussed. Finally, recent published data about alterations in important signaling pathways by exercise are presented.