3vuk
From Proteopedia
Crystal structure of a cysteine-deficient mutant M5 in MAP kinase JNK1
Structural highlights
Disease[JIP1_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] Function[JIP1_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 PubMedIntracellular proteins can have free cysteines that may contribute to their structure, function, and stability; however, free cysteines can lead to chemical instabilities in solution because of oxidation-driven aggregation. The MAP kinase, c-Jun N-terminal kinase 1 (JNK1), possesses seven free cysteines and is an important drug target for autoimmune diseases, cancers, and apoptosis-related diseases. To characterize the role of cysteine residues in the structure, function, and stability of JNK1, we prepared and evaluated wild-type JNK1 and seven cysteine-deficient JNK1 proteins. The nonreduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments showed that the chemical stability of JNK1 increased as the number of cysteines decreased. The contribution of each cysteine residue to biological function and thermal stability was highly susceptible to the environment surrounding the particular cysteine mutation. The mutations of solvent-exposed cysteine to serine did not influence biological function and increased the thermal stability. The mutation of the accessible cysteine involved in the hydrophobic pocket did not affect biological function, although a moderate thermal destabilization was observed. Cysteines in the loosely assembled hydrophobic environment moderately contributed to thermal stability, and the mutations of these cysteines had a negligible effect on enzyme activity. The other cysteines are involved in the tightly filled hydrophobic core, and mutation of these residues was found to correlate with thermal stability and enzyme activity. These findings about the role of cysteine residues should allow us to obtain a stable JNK1 and thus promote the discovery of potent JNK1 inhibitors. Seven cysteine-deficient mutants depict the interplay between thermal and chemical stabilities of individual cysteine residues in mitogen-activated protein kinase c-Jun N-terminal kinase 1.,Nakaniwa T, Fukada H, Inoue T, Gouda M, Nakai R, Kirii Y, Adachi M, Tamada T, Segawa S, Kuroki R, Tada T, Kinoshita T Biochemistry. 2012 Oct 23;51(42):8410-21. doi: 10.1021/bi300918w. Epub 2012 Oct, 11. PMID:23020677[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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