scholarly journals Characterisation of L-Type Amino Acid Transporter 1 (LAT1) Expression in Human Skeletal Muscle by Immunofluorescent Microscopy

Nutrients ◽  
2017 ◽  
Vol 10 (1) ◽  
pp. 23 ◽  
Author(s):  
Nathan Hodson ◽  
Thomas Brown ◽  
Sophie Joanisse ◽  
Nick Aguirre ◽  
Daniel West ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Human Skeletal Muscle ◽  
Amino Acid Transporter ◽  
Immunofluorescent Microscopy ◽  
Acid Transporter

scholarly journals An increase in essential amino acid availability upregulates amino acid transporter expression in human skeletal muscle

2010 ◽  
Vol 298 (5) ◽  
pp. E1011-E1018 ◽  
Author(s):  
Micah J. Drummond ◽  
Erin L. Glynn ◽  
Christopher S. Fry ◽  
Kyle L. Timmerman ◽  
Elena Volpi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Protein Expression ◽  
Human Skeletal Muscle ◽  
Amino Acid Transporter ◽  
Dependent Manner ◽  
Mtorc1 Signaling ◽  
Acid Transporter ◽  
Transporter Expression

Essential amino acids (EAA) stimulate skeletal muscle mammalian target of rapamycin complex 1 (mTORC1) signaling and protein synthesis. It has recently been reported that an increase in amino acid (AA) transporter expression during anabolic conditions is rapamycin-sensitive. The purpose of this study was to determine whether an increase in EAA availability increases AA transporter expression in human skeletal muscle. Muscle biopsies were obtained from the vastus lateralis of seven young adult subjects (3 male, 4 female) before and 1–3 h after EAA ingestion (10 g). Blood and muscle samples were analyzed for leucine kinetics using stable isotopic techniques. Quantitative RT-PCR, and immunoblotting were used to determine the mRNA and protein expression, respectively, of AA transporters and members of the general AA control pathway [general control nonrepressed (GCN2), activating transcription factor (ATF4), and eukaryotic initiation factor (eIF2) α-subunit (Ser52)]. EAA ingestion increased blood leucine concentration, delivery of leucine to muscle, transport of leucine from blood into muscle, intracellular muscle leucine concentration, ribosomal protein S6 (Ser240/244) phosphorylation, and muscle protein synthesis. This was followed with increased L-type AA transporter (LAT1), CD98, sodium-coupled neutral AA transporter (SNAT2), and proton-coupled amino acid transporter (PAT1) mRNA expression at 1 h ( P < 0.05) and modest increases in LAT1 protein expression (3 h post-EAA) and SNAT2 protein expression (2 and 3 h post-EAA, P < 0.05). Although there were no changes in GCN2 expression and eIF2α phosphorylation, ATF4 protein expression reached significance by 2 h post-EAA ( P < 0.05). We conclude that an increase in EAA availability upregulates human skeletal muscle AA transporter expression, perhaps in an mTORC1-dependent manner, which may be an adaptive response necessary for improved AA intracellular delivery.

scholarly journals Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle

2014 ◽  
Vol 116 (11) ◽  
pp. 1353-1364 ◽  
Author(s):  
P. T. Reidy ◽  
D. K. Walker ◽  
J. M. Dickinson ◽  
D. M. Gundermann ◽  
M. J. Drummond ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Whey Protein ◽  
Amino Acid Transport ◽  
Amino Acid Transporter ◽  
Acid Transport ◽  
Amino Acid Availability ◽  
Acid Transporter ◽  
Dairy Protein ◽  
Myofibrillar Protein Synthesis

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups ( P < 0.05). However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein ( P < 0.05). Postexercise myofibrillar protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein.

Skeletal muscle amino acid transporter and BCAT2 expression prior to and following interval running or resistance exercise in mode-specific trained males

Amino Acids ◽  
2018 ◽  
Vol 50 (7) ◽  
pp. 961-965 ◽  
Author(s):  
Paul A. Roberson ◽  
Cody T. Haun ◽  
C. Brooks Mobley ◽  
Matthew A. Romero ◽  
Petey W. Mumford ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Amino Acid Transporter ◽  
Acid Transporter

Skeletal Muscle Amino Acid Transporter mRNA Expression Is Increased In Young And Older Humans Following Resistance Exercise

2010 ◽  
Vol 42 ◽  
pp. 62-63
Author(s):  
Micah J. Drummond ◽  
Christopher S. Fry ◽  
Erin L. Glynn ◽  
Kyle L. Timmerman ◽  
Elena Volpi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Mrna Expression ◽  
Amino Acid Transporter ◽  
Acid Transporter

scholarly journals Insulin increases mRNA abundance of the amino acid transporter SLC7A5/LAT1 via an mTORC1-dependent mechanism in skeletal muscle cells

2014 ◽  
Vol 2 (3) ◽  
pp. e00238 ◽  
Author(s):  
Dillon K. Walker ◽  
Micah J. Drummond ◽  
Jared M. Dickinson ◽  
Michael S. Borack ◽  
Kristofer Jennings ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Muscle Cells ◽  
Amino Acid Transporter ◽  
Mrna Abundance ◽  
Skeletal Muscle Cells ◽  
Acid Transporter ◽  
Dependent Mechanism
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