A Ragulator-BORC Interaction Controls Lysosome Positioning in Response to Amino Acid Availability
Overview
Authors
Affiliations
Lysosomes play key roles in the cellular response to amino acid availability. Depletion of amino acids from the medium turns off a signaling pathway involving the Ragulator complex and the Rag guanosine triphosphatases (GTPases), causing release of the inactive mammalian target of rapamycin complex 1 (mTORC1) serine/threonine kinase from the lysosomal membrane. Decreased phosphorylation of mTORC1 substrates inhibits protein synthesis while activating autophagy. Amino acid depletion also causes clustering of lysosomes in the juxtanuclear area of the cell, but the mechanisms responsible for this phenomenon are poorly understood. Herein we show that Ragulator directly interacts with BLOC-1-related complex (BORC), a multi-subunit complex previously found to promote lysosome dispersal through coupling to the small GTPase Arl8 and the kinesins KIF1B and KIF5B. Interaction with Ragulator exerts a negative regulatory effect on BORC that is independent of mTORC1 activity. Amino acid depletion strengthens this interaction, explaining the redistribution of lysosomes to the juxtanuclear area. These findings thus demonstrate that amino acid availability controls lysosome positioning through Ragulator-dependent, but mTORC1-independent, modulation of BORC.
LAMTOR1 regulates dendritic lysosomal positioning in hippocampal neurons through TRPML1 inhibition.
Sun J, Lin W, Hao X, Baudry M, Bi X Front Cell Neurosci. 2024; 18:1495546.
PMID: 39650798 PMC: 11621854. DOI: 10.3389/fncel.2024.1495546.
Heterogeneity of late endosome/lysosomes shown by multiplexed DNA-PAINT imaging.
Bond C, Hugelier S, Xing J, Sorokina E, Lakadamyali M J Cell Biol. 2024; 224(1).
PMID: 39485275 PMC: 11533445. DOI: 10.1083/jcb.202403116.
Loughran G, De Pace R, Ding N, Zhang J, Jungreis I, Carancini G bioRxiv. 2024; .
PMID: 39372779 PMC: 11451614. DOI: 10.1101/2024.08.30.610563.
LAMTOR1 ablation impedes cGAS degradation caused by chemotherapy and promotes antitumor immunity.
Bie J, Li Y, Song C, Weng Q, Zhao L, Su L Proc Natl Acad Sci U S A. 2024; 121(41):e2320591121.
PMID: 39361643 PMC: 11474068. DOI: 10.1073/pnas.2320591121.
Organelle Communication with the Nucleus.
Sengupta S, Levy D Results Probl Cell Differ. 2024; 73:3-23.
PMID: 39242372 PMC: 11409190. DOI: 10.1007/978-3-031-62036-2_1.