7nzd
Fourth SH3 domain of POSH (Plenty of SH3 Domains protein)
Structural highlights
FunctionSH3R1_HUMAN Has E3 ubiquitin-protein ligase activity. In the absence of an external substrate, it can catalyze self-ubiquitination (PubMed:15659549, PubMed:20696164). Stimulates ubiquitination of potassium channel KCNJ1, enhancing it's dynamin-dependent and clathrin-independent endocytosis (PubMed:19710010). Acts as a scaffold protein that coordinates with MAPK8IP1/JIP1 in organizing different components of the JNK pathway, including RAC1 or RAC2, MAP3K11/MLK3 or MAP3K7/TAK1, MAP2K7/MKK7, MAPK8/JNK1 and/or MAPK9/JNK2 into a functional multiprotein complex to ensure the effective activation of the JNK signaling pathway. Regulates the differentiation of CD4(+) and CD8(+) T-cells and promotes T-helper 1 (Th1) cell differentiation. Regulates the activation of MAPK8/JNK1 and MAPK9/JNK2 in CD4(+) T-cells and the activation of MAPK8/JNK1 in CD8(+) T-cells. Plays a crucial role in the migration of neocortical neurons in the developing brain. Controls proper cortical neuronal migration and the formation of proximal cytoplasmic dilation in the leading process (PCDLP) in migratory neocortical neurons by regulating the proper localization of activated RAC1 and F-actin assembly (By similarity).[UniProtKB:Q69ZI1][1] [2] [3] (Microbial infection) Plays an essential role in the targeting of HIV-1 Gag to the plasma membrane, this function is dependent on it's RING domain, and hence it's E3 ligase activity.[4] 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[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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