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Biochem Biophys Res Commun. 2017 Nov 18;493(2):1129-1135. doi: 10.1016/j.bbrc.2017.09.008. Epub 2017 Sep 5.

Leucine-induced localization of Leucyl-tRNA synthetase in lysosome membrane.

Author information

1
BK21 Plus Program, Department of Senior Healthcare, Graduate School, Eulji University, South Korea.
2
Department of Chemistry, Seoul National University, South Korea.
3
Department of Biophysics and Chemical Biology, Seoul National University, South Korea; Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, South Korea.
4
Medicinal Bioconvergence Research Center, Seoul National University, South Korea.
5
Department of Convergence Medicine, University of Ulsan College of Medicine and Asan Institute for Life Sciences, Asan Medical Center, South Korea.
6
Medicinal Bioconvergence Research Center, Seoul National University, South Korea; Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Technology, College of Pharmacy, Seoul National University, South Korea.
7
BK21 Plus Program, Department of Senior Healthcare, Graduate School, Eulji University, South Korea; Department of Biomedical Laboratory Science, College of Health Sciences, Eulji University, South Korea. Electronic address: jiyoung.mun@eulji.ac.kr.

Abstract

Leucyl-tRNA synthetase (LRS) plays major roles in providing leucine-tRNA and activating mechanistic target of rapamycin complex 1 (mTORC1) through intracellular leucine sensing. mTORC1 activated by amino acids affects the influence on physiology functions including cell proliferation, protein synthesis and autophagy in various organisms. Biochemical results demonstrating leucine sensing have been published, but visual results are lacking. Therefore, we observed the location of LRS with and without leucine using stimulated emission depletion (STED) microscopy one of the super-resolution microscopy and transmission electron microscopy (TEM). This revealed that LRS was translocated to the lysosome on addition of leucine. The translocation was inhibited by treatment with compound BC-LI-0186, disrupting the interaction between RagD and LRS. Immuno-TEM revealed a clear decrease in LRS translocation to the lysosome on addition of the inhibitor. This direct visualization of leucine sensing and LRS translocation to the lysosome was related to mTORC1 activation. To study the relationship between mTORC1 activation and LRS translocation, we monitored the change in autophagy for each condition using TEM and CLSM. The results showed a decrease in autophagy on addition of leucine, demonstrating crosstalk between leucine sensing, LRS translocation, RagD interaction, and mTORC1 activation.

KEYWORDS:

Autophagy; LRS; Leucine; Lysosome; mTORC1

PMID:
28882589
DOI:
10.1016/j.bbrc.2017.09.008
[Indexed for MEDLINE]

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