A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise.
Since activation of the PI3K/(protein kinase B; PKB/akt) pathway has been shown to alter muscle mass and growth, the aim of this study was to determine whether resistance exercise increased insulin like growth factor (IGF) I/phosphoinositide 3-kinase (PI3K) signalling and whether altering PI(3,4,5)P...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2010-07-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC2905373?pdf=render |
| _version_ | 1811336744294940672 |
|---|---|
| author | D Lee Hamilton Andrew Philp Matthew G MacKenzie Keith Baar |
| author_facet | D Lee Hamilton Andrew Philp Matthew G MacKenzie Keith Baar |
| author_sort | D Lee Hamilton |
| collection | DOAJ |
| description | Since activation of the PI3K/(protein kinase B; PKB/akt) pathway has been shown to alter muscle mass and growth, the aim of this study was to determine whether resistance exercise increased insulin like growth factor (IGF) I/phosphoinositide 3-kinase (PI3K) signalling and whether altering PI(3,4,5)P(3) metabolism genetically would increase load induced muscle growth.Acute and chronic resistance exercise in wild type and muscle specific PTEN knockout mice were used to address the role of PI(3,4,5)P(3) regulation in the development of skeletal muscle hypertrophy. Acute resistance exercise did not increase either IGF-1 receptor phosphorylation or IRS1/2 associated p85. Since insulin/IGF signalling to PI3K was unchanged, we next sought to determine whether inactivation of PTEN played a role in load-induced muscle growth. Muscle specific knockout of PTEN resulted in small but significant increases in heart (PTEN(+/+) = 5.00+/-0.02 mg/g, PTEN(-/-) = 5.50+/-0.09 mg/g), and TA (PTEN(+/+) = 1.74+/-0.04 mg/g, PTEN(-/-) = 1.89 +/-0.03) muscle mass, while the GTN, SOL, EDL and PLN remain unchanged. Following ablation, hypertrophy of the PLN, SOL or EDL muscles was similar between PTEN(-/-) and PTEN(+/+) animals. Even though there were some changes in overload-induced PKB and S6K1 phosphorylation, 1 hr following acute resistance exercise there was no difference in the phosphorylation state of S6K1 Thr389 between genotypes.These data suggest that physiological loading does not lead to the enhanced activation of the PI3K/PKB/mTORC1 axis and that neither PI3K activation nor PTEN, and by extension PI(3,4,5)P(3) levels, play a significant role in adult skeletal muscle growth. |
| first_indexed | 2024-04-13T17:44:04Z |
| format | Article |
| id | doaj.art-2e9bd4a211fa40eca84252e76acbbd48 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-04-13T17:44:04Z |
| publishDate | 2010-07-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-2e9bd4a211fa40eca84252e76acbbd482022-12-22T02:37:04ZengPublic Library of Science (PLoS)PLoS ONE1932-62032010-07-0157e1162410.1371/journal.pone.0011624A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise.D Lee HamiltonAndrew PhilpMatthew G MacKenzieKeith BaarSince activation of the PI3K/(protein kinase B; PKB/akt) pathway has been shown to alter muscle mass and growth, the aim of this study was to determine whether resistance exercise increased insulin like growth factor (IGF) I/phosphoinositide 3-kinase (PI3K) signalling and whether altering PI(3,4,5)P(3) metabolism genetically would increase load induced muscle growth.Acute and chronic resistance exercise in wild type and muscle specific PTEN knockout mice were used to address the role of PI(3,4,5)P(3) regulation in the development of skeletal muscle hypertrophy. Acute resistance exercise did not increase either IGF-1 receptor phosphorylation or IRS1/2 associated p85. Since insulin/IGF signalling to PI3K was unchanged, we next sought to determine whether inactivation of PTEN played a role in load-induced muscle growth. Muscle specific knockout of PTEN resulted in small but significant increases in heart (PTEN(+/+) = 5.00+/-0.02 mg/g, PTEN(-/-) = 5.50+/-0.09 mg/g), and TA (PTEN(+/+) = 1.74+/-0.04 mg/g, PTEN(-/-) = 1.89 +/-0.03) muscle mass, while the GTN, SOL, EDL and PLN remain unchanged. Following ablation, hypertrophy of the PLN, SOL or EDL muscles was similar between PTEN(-/-) and PTEN(+/+) animals. Even though there were some changes in overload-induced PKB and S6K1 phosphorylation, 1 hr following acute resistance exercise there was no difference in the phosphorylation state of S6K1 Thr389 between genotypes.These data suggest that physiological loading does not lead to the enhanced activation of the PI3K/PKB/mTORC1 axis and that neither PI3K activation nor PTEN, and by extension PI(3,4,5)P(3) levels, play a significant role in adult skeletal muscle growth.http://europepmc.org/articles/PMC2905373?pdf=render |
| spellingShingle | D Lee Hamilton Andrew Philp Matthew G MacKenzie Keith Baar A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. PLoS ONE |
| title | A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. |
| title_full | A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. |
| title_fullStr | A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. |
| title_full_unstemmed | A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. |
| title_short | A limited role for PI(3,4,5)P3 regulation in controlling skeletal muscle mass in response to resistance exercise. |
| title_sort | limited role for pi 3 4 5 p3 regulation in controlling skeletal muscle mass in response to resistance exercise |
| url | http://europepmc.org/articles/PMC2905373?pdf=render |
| work_keys_str_mv | AT dleehamilton alimitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT andrewphilp alimitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT matthewgmackenzie alimitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT keithbaar alimitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT dleehamilton limitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT andrewphilp limitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT matthewgmackenzie limitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise AT keithbaar limitedroleforpi345p3regulationincontrollingskeletalmusclemassinresponsetoresistanceexercise |