The GATOR–Rag GTPase pathway inhibits mTORC1 activation by lysosome-derived amino acids

Abstract

The mechanistic target of rapamycin complex 1 (mTORC1) couples nutrient sufficiency to cell growth. mTORC1 is activated by exogenously acquired amino acids sensed through the GATOR–Rag guanosine triphosphatase (GTPase) pathway, or by amino acids derived through lysosomal degradation of protein by a poorly defined mechanism. Here, we revealed that amino acids derived from the degradation of protein (acquired through oncogenic Ras-driven macropinocytosis) activate mTORC1 by a Rag GTPase–independent mechanism. mTORC1 stimulation through this pathway required the HOPS complex and was negatively regulated by activation of the GATOR-Rag GTPase pathway. Therefore, distinct but functionally coordinated pathways control mTORC1 activity on late endocytic organelles in response to distinct sources of amino acids.

Endofin is required for HD-PTP and ESCRT-0 interdependent endosomal sorting of ubiquitinated transmembrane cargoes

“…For MiniTurbo BioID studies, streptavidin pulldowns were performed as described previously by Hesketh et al. ( Hesketh et al., 2020 ) and 1/6 of each sample was run on a TripleTOF™ 6600 instrument (AB SCIEX, Concord, Ontario, Canada). Samples were directly loaded at 800 nL/min onto an equilibrated HPLC column and LC-MS/MS was performed on a tripleTOF instrument as previously reported by Hesketh et al.…”

“…Samples were directly loaded at 800 nL/min onto an equilibrated HPLC column and LC-MS/MS was performed on a tripleTOF instrument as previously reported by Hesketh et al. ( Hesketh et al., 2020 ). Samples were analyzed with two separate injections with instrument methods set to data dependent acquisition (DDA) and data independent acquisition (SWATH) modes, as reported previously by Hesketh et al.…”

Toward Understanding the Molecular Role of SNX27/Retromer in Human Health and Disease

“…Retromer knockdown in Drosophila has been shown to disrupt autophagy, when undigested cytoplasmic and endosomal material builds up in autophagosomes (Pim et al, 2015). Retromer has very recently been indirectly implicated in regulation of mTORC1 (Hesketh et al, 2020). Future research is required to understand how SNX27 and/or retromer function alone or together to influence or regulate both autophagy and nutrient sensing.…”

SEA and GATOR 10 Years Later

“…Sea4 also contains a C-terminal RING domain, which, together with its β -propeller and α -solenoid motifs, makes it closely resemble several protein subunits of the homotypic fusion and protein sorting (HOPS) and class C core vacuole/endosome tethering (CORVET) complexes, which have been implicated in the tethering of membranes prior to their fusion. HOPS and CORVET are associated with the vacuoles/lysosomes and endosomes, respectively, and play a role in endosomal and vacuolar assembly and trafficking, as well as in nutrient transport and autophagy [32,37]. Sea2/WDR24 and Sea3/WDR59 also have a C-terminal RING domain.…”

“…A RAG-independent induction of mTORC1 by amino acids both at the vacuole/lysosome and Golgi has also been described in yeast and humans [62][63][64][65], but will not be thoroughly discussed in this review since neither SEA nor GATOR seem to be involved in this mode of mTORC1 activation. Moreover, a recent study revealed that RAG-independent activation of mTORC1 by amino acids derived from protein degradation in lysosomes required HOPS complex and was negatively regulated by activation of the GATOR-RAGs pathway [37]. Thus, evolutionary related HOPS and GATOR2 [3] have similar but divergent roles in activating mTORC1 in response to different amino acid inputs.…”