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From Proteopedia
Mutant V517L of the SH3 domain of JNK-interacting protein 1 (JIP1)
Structural highlights
DiseaseJIP1_HUMAN Defects in MAPK8IP1 are a cause of non-insulin-dependent diabetes mellitus (NIDDM) [MIM:125853. NIDDM is characterized by an autosomal dominant mode of inheritance, onset during adulthood and insulin resistance.[1] FunctionJIP1_HUMAN The JNK-interacting protein (JIP) group of scaffold proteins selectively mediates JNK signaling by aggregating specific components of the MAPK cascade to form a functional JNK signaling module. Required for JNK activation in response to excitotoxic stress. Cytoplasmic MAPK8IP1 causes inhibition of JNK-regulated activity by retaining JNK in the cytoplasm and inhibiting JNK phosphorylation of c-Jun. May also participate in ApoER2-specific reelin signaling. Directly, or indirectly, regulates GLUT2 gene expression and beta-cell function. Appears to have a role in cell signaling in mature and developing nerve terminals. May function as a regulator of vesicle transport, through interactions with the JNK-signaling components and motor proteins (By similarity). Functions as an anti-apoptotic protein and whose level seems to influence the beta-cell death or survival response. Publication Abstract from PubMedAromatic residues cluster in the core of folded proteins, where they stabilize the structure through multiple interactions. Nuclear magnetic resonance (NMR) studies in the 1970s showed that aromatic side chains can undergo ring flips-that is, 180 degrees rotations-despite their role in maintaining the protein fold(1-3). It was suggested that large-scale 'breathing' motions of the surrounding protein environment would be necessary to accommodate these ring flipping events(1). However, the structural details of these motions have remained unclear. Here we uncover the structural rearrangements that accompany ring flipping of a buried tyrosine residue in an SH3 domain. Using NMR, we show that the tyrosine side chain flips to a low-populated, minor state and, through a proteome-wide sequence analysis, we design mutants that stabilize this state, which allows us to capture its high-resolution structure by X-ray crystallography. A void volume is generated around the tyrosine ring during the structural transition between the major and minor state, and this allows fast flipping to take place. Our results provide structural insights into the protein breathing motions that are associated with ring flipping. More generally, our study has implications for protein design and structure prediction by showing how the local protein environment influences amino acid side chain conformations and vice versa. Visualizing protein breathing motions associated with aromatic ring flipping.,Marino Perez L, Ielasi FS, Bessa LM, Maurin D, Kragelj J, Blackledge M, Salvi N, Bouvignies G, Palencia A, Jensen MR Nature. 2022 Feb;602(7898):695-700. doi: 10.1038/s41586-022-04417-6. Epub 2022, Feb 16. PMID:35173330[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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