5y38

From Proteopedia

Crystal structure of C7orf59-HBXIP complex

Structural highlights

5y38 is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.8Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

LTOR5_HUMAN As part of the Ragulator complex it is involved in amino acid sensing and activation of mTORC1, a signaling complex promoting cell growth in response to growth factors, energy levels, and amino acids. Activated by amino acids through a mechanism involving the lysosomal V-ATPase, the Ragulator functions as a guanine nucleotide exchange factor activating the small GTPases Rag. Activated Ragulator and Rag GTPases function as a scaffold recruiting mTORC1 to lysosomes where it is in turn activated. When complexed to BIRC5, interferes with apoptosome assembly, preventing recruitment of pro-caspase-9 to oligomerized APAF1, thereby selectively suppressing apoptosis initiated via the mitochondrial/cytochrome c pathway. Down-regulates hepatitis B virus (HBV) replication.^[1] ^[2]

Publication Abstract from PubMed

Amino acid-dependent activation of the mechanistic target of rapamycin complex 1 (mTORC1) is mediated by Rag GTPases, which are recruited to the lysosome by the Ragulator complex consisting of p18, MP1, p14, HBXIP and C7orf59; however, the molecular mechanism is elusive. Here, we report the crystal structure of Ragulator, in which p18 wraps around the MP1-p14 and C7orf59-HBXIP heterodimers and the interactions of p18 with MP1, C7orf59, and HBXIP are essential for the assembly of Ragulator. There are two binding sites for the Roadblock domains of Rag GTPases: helix alpha1 of p18 and the two helices side of MP1-p14. The interaction of Ragulator with Rag GTPases is required for their cellular co-localization and can be competitively inhibited by C17orf59. Collectively, our data indicate that Ragulator functions as a scaffold to recruit Rag GTPases to lysosomal membrane in mTORC1 signaling.

Structural basis for Ragulator functioning as a scaffold in membrane-anchoring of Rag GTPases and mTORC1.,Zhang T, Wang R, Wang Z, Wang X, Wang F, Ding J Nat Commun. 2017 Nov 9;8(1):1394. doi: 10.1038/s41467-017-01567-4. PMID:29123114^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Marusawa H, Matsuzawa S, Welsh K, Zou H, Armstrong R, Tamm I, Reed JC. HBXIP functions as a cofactor of survivin in apoptosis suppression. EMBO J. 2003 Jun 2;22(11):2729-40. PMID:12773388 doi:10.1093/emboj/cdg263
↑ Bar-Peled L, Schweitzer LD, Zoncu R, Sabatini DM. Ragulator is a GEF for the rag GTPases that signal amino acid levels to mTORC1. Cell. 2012 Sep 14;150(6):1196-208. doi: 10.1016/j.cell.2012.07.032. PMID:22980980 doi:10.1016/j.cell.2012.07.032
↑ Zhang T, Wang R, Wang Z, Wang X, Wang F, Ding J. Structural basis for Ragulator functioning as a scaffold in membrane-anchoring of Rag GTPases and mTORC1. Nat Commun. 2017 Nov 9;8(1):1394. doi: 10.1038/s41467-017-01567-4. PMID:29123114 doi:http://dx.doi.org/10.1038/s41467-017-01567-4