Open AccessMitogen-activated protein kinase (MAPK) pathway activation: effects of age and acute exercise on human skeletal muscle
Author(s) -
David L. Williamson,
Patricia A. Gallagher,
Matthew P. Harber,
Chris Hollon,
Scott Trappe
Publication year - 2003
Publication title -
journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2002.036673
Subject(s) - mapk/erk pathway , phosphorylation , skeletal muscle , p38 mitogen activated protein kinases , protein kinase a , kinase , medicine , muscle biopsy , endocrinology , chemistry , biology , biopsy , microbiology and biotechnology
The purpose of this investigation was to examine the activation (phosphorylation) and total protein content of MAPK signalling cascade proteins (ERK 1/2, p90RSK, Mnk 1, eIF4E, p38 MAPK, JNK/SAPK, MKP 1) at rest and following exercise, in sedentary young and old men. Eight young (22 +/- 1 years; YM) and eight old (79 +/- 3 years; OM) men underwent a resting muscle biopsy of the vastus lateralis; they then performed a knee extensor resistance exercise session (29 contractions at approximately 70 % of max), followed by a post-exercise biopsy. Western immunoblot analysis demonstrated that the OM had higher resting phosphorylation of ERK 1/2, p90RSK, Mnk 1, p38 MAPK and JNK/SAPK proteins versus YM (P < 0.05). The resistance exercise bout caused an increase in phosphorylation of the ERK 1/2, p90RSK and Mnk 1 proteins (P < 0.05) in the YM. Conversely, the OM had a decrease in ERK 1/2, p90RSK, Mnk 1, p38 MAPK and JNK/SAPK phosphorylation (P < 0.05) after the exercise bout. Neither group showed a change in eIF4E phosphorylation. The total amount of protein expression of the MAPK signalling proteins was not different between the YM and OM, except that there was a higher (P < 0.05) MKP 1 protein content in the OM. This investigation is the first to provide evidence that MAPK proteins are differentially activated at rest and in response to a bout of resistance exercise in skeletal muscle of young and old men. These findings may have implications for other processes (e.g. transcription and translation) involved in skeletal muscle type and growth, when examining the changes occurring with ageing muscle before and after resistance exercise/training.