2kio
NMR structure of the oxidized yeast TOR1 FATC domain bound to DPC micelles at 318K
Structural highlights
FunctionTOR1_YEAST Phosphatidylinositol 3-kinase homolog, component of TORC1, which regulates multiple cellular processes to control cell growth in response to environmental signals. Nutrient limitation and environmental stress signals cause inactivation of TORC1. Active TORC1 positively controls ribosome biogenesis via control of rRNA, ribosomal protein and tRNA gene expression, and rRNA processing. TORC1 positively controls protein biosynthesis by regulation of mRNA stability, translation initiation factor activity, and high-affinity amino acid permeases that serve to provide amino acids for use by the translation machinery. TORC1 also promotes growth by sequestering a number of nutrient and general stress-responsive transcription factors in the cytoplasm. TORC1 negatively controls macroautophagy, a process to recycle surplus cytoplasmic mass under nutrient starvation conditions. TORC1 controls many of these processes via TIP41-TAP42-mediated inhibition of the type 2A-related phosphatases PP2A and SIT4.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe target of rapamycin (TOR) is a conserved eukaryotic Ser/Thr kinase that regulates cellular growth in response to the nutrient and energy state. TOR signaling plays an important role in the development of diseases such as cancer, obesity, and diabetes and in different redox-sensitive processes (hypoxia, apoptosis, and aging). Because TOR has been detected at different cellular membranes and in the nucleus, its localization may influence the specific signaling readout. To better understand how TOR can associate with different membranes, the lipid-binding properties of the redox-sensitive yeast TOR1 FATC domain (y1fatc) have been characterized by solution NMR spectroscopy. Binding studies with different lipids indicate that y1fatc interacts specifically with a membrane-mimetic environment but appears not to recognize a specific lipid headgroup. In both, the structures of oxidized and reduced micelle-bound y1fatc, residues Ile-2456 to Trp-2470 of the lipid-binding motif form a hydrophobic bulb that has a rim of charged residues. The diffusion constants for both micelle-bound states are consistent with the rotational correlation times from the analysis of the (15)N relaxation data. Based on the K(d) values, the oxidized form (K(d) approximately 0.31 mm) binds dodecyl phosphocholine micelles slightly tighter than the reduced form (K(d) approximately 1.86 mM). Binding studies with y1fatc in which one or both tryptophans (Trp-2466 and Trp-2470) were replaced by alanine suggest that these residues are important for the exact positioning in the membrane and that the other aromatic (His-2462, Tyr-2463, and Phe-2469) and aliphatic residues (Ile-2456, Leu-2459, Ile-2464, and Pro-2468) in the lipid-binding motif contribute significantly to the affinity. Structural basis for the association of the redox-sensitive target of rapamycin FATC domain with membrane-mimetic micelles.,Dames SA J Biol Chem. 2010 Mar 5;285(10):7766-75. Epub 2009 Dec 30. PMID:20042596[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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