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Publication Abstract from PubMed

The target of rapamycin complex 1 (TORC1) integrates various hormonal and nutrient signals to regulate cell growth, proliferation, and differentiation. Amino acid-dependent activation of TORC1 is mediated via the yeast EGO complex (EGOC) consisting of Gtr1, Gtr2, Ego1, and Ego3. Here, we identify the previously uncharacterized Ycr075w-a/Ego2 protein as an additional EGOC component that is required for the integrity and localization of the heterodimeric Gtr1-Gtr2 GTPases, equivalent to mammalian Rag GTPases. We also report the crystal structure of the Ego1-Ego2-Ego3 ternary complex (EGO-TC) at 2.4 A resolution, in which Ego2 and Ego3 form a heterodimer flanked along one side by Ego1. Structural data also reveal the structural conservation of protein components between the yeast EGO-TC and the human Ragulator, which acts as a GEF for Rag GTPases. Interestingly, however, artificial tethering of Gtr1-Gtr2 to the vacuolar membrane is sufficient to activate TORC1 in response to amino acids even in the absence of the EGO-TC. Our structural and functional data therefore support a model in which the EGO-TC acts as a scaffold for Rag GTPases in TORC1 signaling.Cell Research advance online publication 24 July 2015; doi:10.1038/cr.2015.86.

Crystal structure of the Ego1-Ego2-Ego3 complex and its role in promoting Rag GTPase-dependent TORC1 signaling.,Powis K, Zhang T, Panchaud N, Wang R, De Virgilio C, Ding J Cell Res. 2015 Jul 24. doi: 10.1038/cr.2015.86. PMID:26206314^[3]

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