PMID- 19112158
OWN - NLM
STAT- MEDLINE
DCOM- 20090529
LR  - 20211203
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 106
IP  - 4
DP  - 2009 Apr
TI  - Maximal lengthening contractions induce different signaling responses in the type 
      I and type II fibers of human skeletal muscle.
PG  - 1412-8
LID - 10.1152/japplphysiol.91243.2008 [doi]
AB  - The molecular mechanisms by which resistance exercise enlarges muscle mass, 
      particularly the mass of fast-twitch type II fibers, are likely to involve 
      enhanced phosphorylation/activation of key enzymes regulating protein synthesis. 
      The hypothesis is that resistance exercise influences the phosphorylation of such 
      key signaling proteins to a greater extent in type II than in type I fibers. Six 
      recreationally active male subjects performed four sets of six maximal 
      lengthening contractions with one leg. Muscle biopsies were taken from the vastus 
      lateralis before and immediately after exercise and following 1 and 2 h of 
      recovery. Samples were freeze-dried, and individual muscle fibers were dissected 
      out and identified as type I or type II after staining for myosin ATPase. 
      Phosphorylation of p70(S6k) on Thr(389) and S6 in type II fibers was increased 
      three-to fourfold and six- to ninefold (P < 0.05), respectively, 1 and 2 h after 
      exercise, whereas phosphorylation in type I fibers remained unchanged. 
      Phosphorylation of Akt, mammalian target of rapamycin (mTOR) and AMP-activated 
      protein kinase (AMPK) was unaltered in both fiber types, whereas that of 
      eukaryotic elongation factor 2 (eEF2) was attenuated 20-45% (P < 0.05) in type II 
      fibers during recovery. Phosphorylation of ERK1/2 was elevated six- to sevenfold 
      (P < 0.05) immediately after exercise, and p38 MAPK phosphorylation was increased 
      three- to fourfold (P < 0.05) for as long as 1 h after exercise in both types of 
      fibers, although the level was markedly higher in type II fibers (P < 0.05). In 
      conclusion, the elevation of p70(S6k) and the reduction of eEF2 phosphorylation 
      in the type II fibers following resistance exercise suggest stimulation of 
      protein synthesis, which may contribute to a more pronounced enlargement of these 
      fibers. Our findings also suggest that p70(S6k) is activated, at least in part, 
      via pathways not involving Akt-mTOR and MAPK.
FAU - Tannerstedt, Jorgen
AU  - Tannerstedt J
AD  - Astrand Laboratory, Swedish School of Sport and Health Sciences, Box 5626, 
      Stockholm, S-114 86 Sweden.
FAU - Apro, William
AU  - Apro W
FAU - Blomstrand, Eva
AU  - Blomstrand E
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20081226
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Peptide Elongation Factor 2)
RN  - EC 2.7.- (Protein Kinases)
RN  - EC 2.7.1.1 (MTOR protein, human)
RN  - EC 2.7.11.1 (Oncogene Protein v-akt)
RN  - EC 2.7.11.1 (Ribosomal Protein S6 Kinases, 70-kDa)
RN  - EC 2.7.11.1 (TOR Serine-Threonine Kinases)
RN  - EC 2.7.11.11 (Cyclic AMP-Dependent Protein Kinases)
RN  - EC 2.7.11.24 (Extracellular Signal-Regulated MAP Kinases)
RN  - EC 2.7.11.24 (p38 Mitogen-Activated Protein Kinases)
RN  - EC 3.6.4.1 (Myosin Heavy Chains)
SB  - IM
MH  - Adult
MH  - Blotting, Western
MH  - Cyclic AMP-Dependent Protein Kinases/metabolism
MH  - Extracellular Signal-Regulated MAP Kinases/metabolism
MH  - Humans
MH  - Male
MH  - Muscle Contraction/*physiology
MH  - Muscle Fibers, Fast-Twitch/*physiology
MH  - Muscle Fibers, Slow-Twitch/*physiology
MH  - Muscle, Skeletal/cytology/*physiology
MH  - Myosin Heavy Chains/metabolism
MH  - Oncogene Protein v-akt/biosynthesis/genetics
MH  - Peptide Elongation Factor 2/biosynthesis
MH  - Phosphorylation
MH  - Protein Kinases/biosynthesis/genetics
MH  - Ribosomal Protein S6 Kinases, 70-kDa/biosynthesis/genetics
MH  - Signal Transduction/physiology
MH  - TOR Serine-Threonine Kinases
MH  - p38 Mitogen-Activated Protein Kinases/metabolism
EDAT- 2008/12/30 09:00
MHDA- 2009/05/30 09:00
CRDT- 2008/12/30 09:00
PHST- 2008/12/30 09:00 [entrez]
PHST- 2008/12/30 09:00 [pubmed]
PHST- 2009/05/30 09:00 [medline]
AID - 91243.2008 [pii]
AID - 10.1152/japplphysiol.91243.2008 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 2009 Apr;106(4):1412-8. doi: 
      10.1152/japplphysiol.91243.2008. Epub 2008 Dec 26.