5lw1
From Proteopedia
Crystal structure of DARPin-DARPin rigid fusion, variant DD_232_11_D12 in complex JNK1a1 and JIP1 peptide
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. [MK08_HUMAN] Serine/threonine-protein kinase involved in various processes such as cell proliferation, differentiation, migration, transformation and programmed cell death. Extracellular stimuli such as proinflammatory cytokines or physical stress stimulate the stress-activated protein kinase/c-Jun N-terminal kinase (SAP/JNK) signaling pathway. In this cascade, two dual specificity kinases MAP2K4/MKK4 and MAP2K7/MKK7 phosphorylate and activate MAPK8/JNK1. In turn, MAPK8/JNK1 phosphorylates a number of transcription factors, primarily components of AP-1 such as JUN, JDP2 and ATF2 and thus regulates AP-1 transcriptional activity. Phosphorylates the replication licensing factor CDT1, inhibiting the interaction between CDT1 and the histone H4 acetylase HBO1 to replication origins. Loss of this interaction abrogates the acetylation required for replication initiation. Promotes stressed cell apoptosis by phosphorylating key regulatory factors including p53/TP53 and Yes-associates protein YAP1. In T-cells, MAPK8 and MAPK9 are required for polarized differentiation of T-helper cells into Th1 cells. Contributes to the survival of erythroid cells by phosphorylating the antagonist of cell death BAD upon EPO stimulation. Mediates starvation-induced BCL2 phosphorylation, BCL2 dissociation from BECN1, and thus activation of autophagy. Phosphorylates STMN2 and hence regulates microtubule dynamics, controlling neurite elongation in cortical neurons. In the developing brain, through its cytoplasmic activity on STMN2, negatively regulates the rate of exit from multipolar stage and of radial migration from the ventricular zone. Phosphorylates several other substrates including heat shock factor protein 4 (HSF4), the deacetylase SIRT1, ELK1, or the E3 ligase ITCH.[2] [3] [4] [5] [6] [7] [8] [9] JNK1 isoforms display different binding patterns: beta-1 preferentially binds to c-Jun, whereas alpha-1, alpha-2, and beta-2 have a similar low level of binding to both c-Jun or ATF2. However, there is no correlation between binding and phosphorylation, which is achieved at about the same efficiency by all isoforms.[10] [11] [12] [13] [14] [15] [16] [17] Publication Abstract from PubMedTo untangle the complex signaling of the c-Jun N-terminal kinase (JNK) isoforms, we need tools that can selectively detect and inhibit individual isoforms. Because of the high similarity between JNK1, JNK2 and JNK3, it is very difficult to generate small-molecule inhibitors with this discriminatory power. Thus, we have recently selected protein binders from the designed ankyrin repeat protein (DARPin) library which were indeed isoform-specific inhibitors of JNK1 with low nanomolar potency. Here we provide the structural basis for their isotype discrimination and their inhibitory action. All our previous attempts to generate crystal structures of complexes had failed. We have now made use of a technology we recently developed which consists of rigid fusion of an additional special DARPin, which acts as a crystallization enhancer. This can be rigidly fused with different geometries, thereby generating a range of alternative crystal packings. The structures reveal the molecular basis for isoform specificity of the DARPins and their ability to prevent JNK activation and may thus form the basis of further investigation of the JNK family as well as novel approaches to drug design. Structural Basis for the Selective Inhibition of c-Jun N-Terminal Kinase 1 Determined by Rigid DARPin-DARPin Fusions.,Wu Y, Honegger A, Batyuk A, Mittl PRE, Pluckthun A J Mol Biol. 2018 Jul 6;430(14):2128-2138. doi: 10.1016/j.jmb.2017.10.032. Epub, 2017 Nov 8. PMID:29126898[18] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Human | Large Structures | Mitogen-activated protein kinase | Synthetic construct sequences | Batyuk, A | Honegger, A | Mittl, P R | Plueckthun, A | Wu, Y | De novo protein | Designed ankyrin repeat protein | Protein design | Protein engineering | Rigid domain fusion | Transferase | X-ray crystallography
