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

Research output: Contribution to journalArticlepeer-review

Authors

  • Nathan Hodson
  • Thomas Brown
  • Sophie Joanisse
  • Nick Aguirre
  • Daniel W. D. West
  • Daniel R. Moore
  • Keith Baar

Colleges, School and Institutes

External organisations

  • University of California Davis
  • University of Toronto

Abstract

The branch chain amino acid leucine is a potent stimulator of protein synthesis in skeletal muscle. Leucine rapidly enters the cell via the L-Type Amino Acid Transporter 1 (LAT1); however, little is known regarding the localisation and distribution of this transporter in human skeletal muscle. Therefore, we applied immunofluorescence staining approaches to visualise LAT1 in wild type (WT) and LAT1 muscle-specific knockout (mKO) mice, in addition to basal human skeletal muscle samples. LAT1 positive staining was visually greater in WT muscles compared to mKO muscle. In human skeletal muscle, positive LAT1 staining was noted close to the sarcolemmal membrane (dystrophin positive staining), with a greater staining intensity for LAT1 observed in the sarcoplasmic regions of type II fibres (those not stained positively for myosin heavy-chain 1, Type II-25.07 ± 5.93, Type I-13.71 ± 1.98,p< 0.01), suggesting a greater abundance of this protein in these fibres. Finally, we observed association with LAT1 and endothelial nitric oxide synthase (eNOS), suggesting LAT1 association close to the microvasculature. This is the first study to visualise the distribution and localisation of LAT1 in human skeletal muscle. As such, this approach provides a validated experimental platform to study the role and regulation of LAT1 in human skeletal muscle in response to various physiological and pathophysiological models.

Details

Original languageEnglish
Article number23
JournalNutrients
Volume10
Issue number1
Publication statusPublished - 26 Dec 2017

Keywords

  • LAT1 , leucine , protein , amino acid transport