1veu
From Proteopedia
Crystal structure of the p14/MP1 complex at 2.15 A resolution
Structural highlights
FunctionLTOR3_MOUSE 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. Adapter protein that enhances the efficiency of the MAP kinase cascade facilitating the activation of MAPK2.[1] [2] 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 PubMedSignaling pathways in eukaryotic cells are often controlled by the formation of specific signaling complexes, which are coordinated by scaffold and adaptor proteins. Elucidating their molecular architecture is essential to understand the spatial and temporal regulation of cellular signaling. p14 and MP1 form a tight (K(d) = 12.8 nM) endosomal adaptor/scaffold complex, which regulates mitogen-activated protein kinase (MAPK) signaling. Here, we present the 1.9-A crystal structure of a biologically functional p14/MP1 complex. The overall topology of the individual MP1 and p14 proteins is almost identical, having a central five-stranded beta-sheet sandwiched between a two-helix and a one-helix layer. Formation of the p14/MP1 heterodimer proceeds by beta-sheet augmentation and yields a unique, almost symmetrical, complex with several potential protein-binding sites on its surface. Mutational analysis allowed identification of the p14 endosomal adaptor motif, which seems to orient the complex relative to the endosomal membrane. Two highly conserved and hydrophobic protein-binding sites are located on the opposite "cytoplasmic" face of the p14/MP1 heterodimer and might therefore function as docking sites for the target proteins extracellular regulated kinase (ERK) 1 and MAPK/ERK kinase 1. Furthermore, detailed sequence analyses revealed that MP1/p14, together with profilins, define a protein superfamily of small subcellular adaptor proteins, named ProflAP. Taken together, the presented work provides insight into the spatial regulation of MAPK signaling, illustrating how p14 and MP1 collaborate as an endosomal adaptor/scaffold complex. Crystal structure of the p14/MP1 scaffolding complex: how a twin couple attaches mitogen-activated protein kinase signaling to late endosomes.,Kurzbauer R, Teis D, de Araujo ME, Maurer-Stroh S, Eisenhaber F, Bourenkov GP, Bartunik HD, Hekman M, Rapp UR, Huber LA, Clausen T Proc Natl Acad Sci U S A. 2004 Jul 27;101(30):10984-9. Epub 2004 Jul 19. PMID:15263099[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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