9oti
From Proteopedia
GATOR2 complex bound to arginine sensor CASTOR1
Structural highlights
FunctionMIOS_HUMAN As a component of the GATOR2 complex, functions as an activator of the amino acid-sensing branch of the mTORC1 signaling pathway (PubMed:23723238, PubMed:26586190, PubMed:27487210, PubMed:35831510, PubMed:36528027). The GATOR2 complex indirectly activates mTORC1 through the inhibition of the GATOR1 subcomplex (PubMed:23723238, PubMed:26586190, PubMed:27487210, PubMed:35831510, PubMed:36528027). GATOR2 probably acts as an E3 ubiquitin-protein ligase toward GATOR1 (PubMed:36528027). In the presence of abundant amino acids, the GATOR2 complex mediates ubiquitination of the NPRL2 core component of the GATOR1 complex, leading to GATOR1 inactivation (PubMed:36528027). In the absence of amino acids, GATOR2 is inhibited, activating the GATOR1 complex (PubMed:25263562, PubMed:25457612, PubMed:26586190, PubMed:27487210). Within the GATOR2 complex, MIOS is required to prevent autoubiquitination of WDR24, the catalytic subunit of the complex (PubMed:35831510). The GATOR2 complex is required for brain myelination (By similarity).[UniProtKB:Q8VE19][1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedMechanistic target of rapamycin complex 1 (mTORC1) is a nutrient-responsive master regulator of metabolism. Amino acids control the recruitment and activation of mTORC1 at the lysosome through the nucleotide loading state of the heterodimeric Rag GTPases. Under low nutrients, including arginine, the GTPase-activating protein complex GATOR1 promotes GTP hydrolysis on RagA/B, inactivating mTORC1. GATOR1 is regulated by the cage-like GATOR2 complex and cytosolic amino acid sensors. To understand how the arginine sensor CASTOR1 binds to GATOR2 to disinhibit GATOR1 under low cytosolic arginine, we determined the cryo-electron microscopy structure of human GATOR2 bound to CASTOR1 in the absence of arginine. Two MIOS WD40 domain beta-propellers of the GATOR2 cage engage with both subunits of a single CASTOR1 homodimer. Each propeller binds to a negatively charged MIOS-binding interface on CASTOR1 that is distal to the arginine pocket. The structure shows how arginine-triggered loop ordering in CASTOR1 blocks the MIOS-binding interface, switches off its binding to GATOR2 and, thus, communicates to downstream mTORC1 activation. Structural basis for mTORC1 regulation by the CASTOR1-GATOR2 complex.,Jansen RM, Maghe C, Tapia K, Wu S, Yang S, Ren X, Zoncu R, Hurley JH Nat Struct Mol Biol. 2025 Jul 25:10.1038/s41594-025-01635-0. doi: , 10.1038/s41594-025-01635-0. PMID:40715445[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||
