File(s) under permanent embargo
Exercise does not alter subcellular localization, but increases phosphorylation of insulin-signaling proteins in human skeletal muscle
journal contribution
posted on 2006-01-01, 00:00 authored by C Wilson, Mark Hargreaves, Kirsten HowlettKirsten HowlettThe subcellular localization of insulin signaling proteins is altered by various stimuli such as insulin, insulin-like growth factor I, and oxidative stress and is thought to be an important mechanism that can influence intracellular signal transduction and cellular function. This study examined the possibility that exercise may also alter the subcellular localization of insulin signaling proteins in human skeletal muscle. Nine untrained males performed 60 min of cycling exercise (~67% peak pulmonary O2 uptake). Muscle biopsies were sampled at rest, immediately after exercise, and 3 h postexercise. Muscle was fractionated by centrifugation into the following crude fractions: cytosolic, nuclear, and a high-speed pellet containing membrane and cytoskeletal components. Fractions were analyzed for protein content of insulin receptor, insulin receptor substrate (IRS)-1 and -2, p85 subunit of phosphatidylinositol 3-kinase, Akt, and glycogen synthase kinase-3 (GSK-3). There was no significant change in the protein content of the insulin signaling proteins in any of the crude fractions after exercise or 3 h postexercise. Exercise had no significant effect on the phosphorylation of IRS-1 Tyr612 in any of the fractions. In contrast, exercise increased (P < 0.05) the phosphorylation of Akt Ser473 and GSK-3α/ß Ser9/21 in the cytosolic fraction only. In conclusion, exercise can increase phosphorylation of downstream insulin signaling proteins specifically in the cytosolic fraction but does not result in changes in the subcellular localization of insulin signaling proteins in human skeletal muscle. Change in the subcellular protein localization is therefore an unlikely mechanism to influence signal transduction pathways and cellular function in skeletal muscle after exercise.
History
Journal
American journal of physiology: endocrinology and metabolismVolume
290Issue
2Pagination
341 - 346Publisher
American Physiological SocietyLocation
Bethesda, Md.Publisher DOI
ISSN
0193-1849eISSN
1522-1555Language
engPublication classification
C1 Refereed article in a scholarly journal; C Journal articleCopyright notice
2006, American Physiological SocietyUsage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC