RESUMO
mTOR enzyme belongs to a family of specific serine/threonine protein kinases. mTOR plays an important role in the transmission of extracellular signals by phosphorylation of various substrates in many metabolic reactions in humans. Protein mTOR, having protein kinase activity, is encoded by a gene FRAP1, which is localized on chromosome 1 (1p36.2) in skeletal muscle. It exists in two mTOR protein complexes mTORC1 and mTORC2 with various sensitivity to the inhibitory effect of rapamycin. mTOR regulates metabolism in skeletal muscle by phosphorylation of various of protein metabolizing enzymes as well as transcription and translation factors. mTOR expression occurs in response to metabolic requests of muscles and leads to increased metabolism of proteins. The data of recent studies suggest an important role of mTOR in the regulation of intracellular metabolism and point to the need of studying the molecular mechanisms involved in physiological function of skeletal muscles.
Assuntos
Músculo Esquelético/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina , Alvo Mecanístico do Complexo 2 de Rapamicina , Complexos Multiproteicos/metabolismo , Músculo Esquelético/fisiologia , Fosforilação , Biossíntese de Proteínas/genética , Sirolimo/metabolismoRESUMO
The enzyme Akt 1 is a member of serine/threonine specific protein kinases family. Akt plays an important role in the transmission of extracellular signals and mechanical stimuli via phosphorylation of its numerous substrates involved in anabolic and catabolic processes as well as mechanical responses of skeletal muscle. Expression of the Akt is increased during skeletal muscle hypertrophy and decreased during muscle atrophy. The G205T polymorphism of Akt is associated with transcriptional activity of the gene in muscle cells and, respectively, with skeletal muscle phenotypes.
Assuntos
Músculo Esquelético/metabolismo , Atrofia Muscular/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Regulação da Expressão Gênica/genética , Humanos , Músculo Esquelético/enzimologia , Atrofia Muscular/enzimologia , Atrofia Muscular/patologia , Fosforilação , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais/genéticaAssuntos
Consumo de Oxigênio , Resistência Física , Polimorfismo de Fragmento de Restrição , Esportes/fisiologia , Adulto , Teste de Esforço , Feminino , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio/genética , Consumo de Oxigênio/fisiologia , Resistência Física/genética , Resistência Física/fisiologia , PrognósticoRESUMO
Muscle fiber composition of m. vastus lateralis has significant individual variability mainly depending on genetic factors. Present study shows analysis of association between polymorphisms of three muscle performance-related genes and muscle fiber type composition in 48 young healthy men. DNA was obtained from mouthwash samples by alkaline extraction. Polymorphism determination of PPARalpha, ACE and ACTN3 genes was performed using polymerase chain raction. Muscle fiber typing from m. vastus lateralis was performed using immunohistochemistry method. We found an association of increased frequency of intron 7 G allele of PPARalpha gene (93.9% vs 60.0%) and D allele of ACE gene (68.8% vs 34.4%) in the group with the highest proportion of slow-twitch fibers (56-70%) compared to the group with the lowest proportion (25-43%). Thus, PPARalpha and ACE genes can be considered as potential candidate genes for muscle fiber type determination.
