Structural snapshots of RAF kinase interactions

2018 ◽  
Vol 46 (6) ◽  
pp. 1393-1406 ◽  
Author(s):  
Soheila Rezaei Adariani ◽  
Marcel Buchholzer ◽  
Mohammad Akbarzadeh ◽  
Saeideh Nakhaei-Rad ◽  
Radovan Dvorsky ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Protein Interactions ◽  
Membrane Lipids ◽  
Control Cell ◽  
Mitogen Activated Protein Kinase ◽  
Regulatory Domains ◽  
Raf Kinase ◽  
Rich Domain ◽  
Molecular Events ◽  
Mitogen Activated Protein

RAF (rapidly accelerated fibrosarcoma) Ser/Thr kinases (ARAF, BRAF, and CRAF) link the RAS (rat sarcoma) protein family with the MAPK (mitogen-activated protein kinase) pathway and control cell growth, differentiation, development, aging, and tumorigenesis. Their activity is specifically modulated by protein–protein interactions, post-translational modifications, and conformational changes in specific spatiotemporal patterns via various upstream regulators, including the kinases, phosphatase, GTPases, and scaffold and modulator proteins. Dephosphorylation of Ser-259 (CRAF numbering) and dissociation of 14-3-3 release the RAF regulatory domains RAS-binding domain and cysteine-rich domain for interaction with RAS-GTP and membrane lipids. This, in turn, results in RAF phosphorylation at Ser-621 and 14-3-3 reassociation, followed by its dimerization and ultimately substrate binding and phosphorylation. This review focuses on structural understanding of how distinct binding partners trigger a cascade of molecular events that induces RAF kinase activation.

scholarly journals Identification of the functional components of the Ras signaling pathway regulating pituitary cell-specific gene expression.

1994 ◽  
Vol 14 (3) ◽  
pp. 1553-1565 ◽  
Author(s):  
K E Conrad ◽  
J M Oberwetter ◽  
R Vaillancourt ◽  
G L Johnson ◽  
A Gutierrez-Hartmann
Keyword(s):  
Gene Expression ◽  
Pituitary Cell ◽  
Mitogen Activated Protein Kinase ◽  
Specific Gene ◽  
Ras Signaling ◽  
Raf Kinase ◽  
Prolactin Gene ◽  
Ras Signaling Pathway ◽  
Mitogen Activated Protein ◽  
Prolactin Promoter

Ras, a small GTP-binding protein, is required for functional receptor tyrosine kinase signaling. Ultimately, Ras alters the activity of specific nuclear transcription factors and regulates novel patterns of gene expression. Using a rat prolactin promoter construct in transient transfection experiments, we show that both oncogenic Ras and activated forms of Raf-1 kinase selectively stimulated the cellular rat prolactin promoter in GH4 rat pituitary cells. We also show that the Ras signal is completely blocked by an expression vector encoding a dominant-negative Raf kinase. Additionally, using a molecular genetic approach, we determined that inhibitory forms of p42 mitogen-activated protein kinase and an Ets-2 transcription factor interfere with both the Ras and the Raf activation of the rat prolactin promoter. These findings define a functional requirement for these signaling constituents in the activation of the prolactin gene, a cell-specific gene which marks the lactotroph pituitary cell type. Further, this analysis allowed us to order the components in the Ras signaling pathway as it impinges on regulation of prolactin gene transcription as Ras-->Raf kinase-->mitogen-activated protein kinase-->Ets. In contrast, we show that intact c-Jun expression inhibited the Ras-induced activation of the prolactin promoter, defining it as a negative regulator of this pathway, whereas c-Jun was able to enhance the Ras activation of an AP-1-driven promoter in GH4 cells. These data show that c-Jun is not the nuclear mediator of the Ras signal for the highly specialized, pituitary cell-specific prolactin cellular promoter. Thus, we have defined a model system which provides an ideal paradigm for studying Ras/Raf signaling pathways and their effects on neuroendocrine cell-specific gene regulation.

scholarly journals Computational Study on the Effect of Inactivating/Activating Mutations on the Inhibition of MEK1 by Trametinib

2020 ◽  
Vol 21 (6) ◽  
pp. 2167
Author(s):  
Jingxuan Zhu ◽  
Congcong Li ◽  
Hengzheng Yang ◽  
Xiaoqing Guo ◽  
Tianci Huang ◽  
...  
Keyword(s):  
Molecular Dynamic ◽  
Conformational Changes ◽  
Computational Study ◽  
Md Simulations ◽  
Mek Inhibitor ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Lung Cancers ◽  
Mitogen Activated Protein ◽  
Alk Positive

Activation of the mitogen-activated protein kinase (MAPK) signaling pathway regulated by human MAP kinase 1 (MEK1) is associated with the carcinogenesis and progression of numerous cancers. In addition, two active mutations (P124S and E203K) have been reported to enhance the activity of MEK1, thereby eventually leading to the tumorigenesis of cancer. Trametinib is an MEK1 inhibitor for treating EML4-ALK-positive, EGFR-activated, and KRAS-mutant lung cancers. Therefore, in this study, molecular docking and molecular dynamic (MD) simulations were performed to explore the effects of inactive/active mutations (A52V/P124S and E203K) on the conformational changes of MEK1 and the changes in the interaction of MEK1 with trametinib. Moreover, steered molecular dynamic (SMD) simulations were further utilized to compare the dissociation processes of trametinib from the wild-type (WT) MEK1 and two active mutants (P124S and E203K). As a result, trametinib had stronger interactions with the non-active MEK1 (WT and A52V mutant) than the two active mutants (P124S and E203K). Moreover, two active mutants may make the allosteric channel of MEK1 wider and shorter than that of the non-active types (WT and A52V mutant). Hence, trametinib could dissociate from the active mutants (P124S and E203K) more easily compared with the WT MEK1. In summary, our theoretical results demonstrated that the active mutations may attenuate the inhibitory effects of MEK inhibitor (trametinib) on MEK1, which could be crucial clues for future anti-cancer treatment.

scholarly journals Phosphorylation of Msx1 promotes cell proliferation through the Fgf9/18-MAPK signaling pathway during embryonic limb development

2020 ◽  
Vol 48 (20) ◽  
pp. 11452-11467
Author(s):  
Yenan Yang ◽  
Xiaoli Zhu ◽  
Xiang Jia ◽  
Wanwan Hou ◽  
Guoqiang Zhou ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Limb Development ◽  
Early Stage ◽  
Control Cell ◽  
Cell Lineage ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Embryonic Limb ◽  
Underlying Mechanisms

Abstract Msh homeobox (Msx) is a subclass of homeobox transcriptional regulators that control cell lineage development, including the early stage of vertebrate limb development, although the underlying mechanisms are not clear. Here, we demonstrate that Msx1 promotes the proliferation of myoblasts and mesenchymal stem cells (MSCs) by enhancing mitogen-activated protein kinase (MAPK) signaling. Msx1 directly binds to and upregulates the expression of fibroblast growth factor 9 (Fgf9) and Fgf18. Accordingly, knockdown or antibody neutralization of Fgf9/18 inhibits Msx1-activated extracellular signal-regulated kinase 1/2 (Erk1/2) phosphorylation. Mechanistically, we determined that the phosphorylation of Msx1 at Ser136 is critical for enhancing Fgf9 and Fgf18 expression and cell proliferation, and cyclin-dependent kinase 1 (CDK1) is apparently responsible for Ser136 phosphorylation. Furthermore, mesenchymal deletion of Msx1/2 results in decreased Fgf9 and Fgf18 expression and Erk1/2 phosphorylation, which leads to serious defects in limb development in mice. Collectively, our findings established an important function of the Msx1-Fgf-MAPK signaling axis in promoting cell proliferation, thus providing a new mechanistic insight into limb development.

scholarly journals An ultrasensitive fiveplex activity assay for cellular kinases

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Christian M. Smolko ◽  
Kevin A. Janes
Keyword(s):  
Protein Kinase ◽  
Protein Interactions ◽  
Posttranslational Modifications ◽  
Large Scale ◽  
Cell Types ◽  
Mitogen Activated Protein Kinase ◽  
Activity Measurement ◽  
Kinase Substrate ◽  
Iκb Kinase ◽  
Mitogen Activated Protein

AbstractProtein kinases are enzymes whose abundance, protein-protein interactions, and posttranslational modifications together determine net signaling activity in cells. Large-scale data on cellular kinase activity are limited, because existing assays are cumbersome, poorly sensitive, low throughput, and restricted to measuring one kinase at a time. Here, we surmount the conventional hurdles of activity measurement with a multiplexing approach that leverages the selectivity of individual kinase-substrate pairs. We demonstrate proof of concept by designing an assay that jointly measures activity of five pleiotropic signaling kinases: Akt, IκB kinase (IKK), c-jun N-terminal kinase (JNK), mitogen-activated protein kinase (MAPK)-extracellular regulated kinase kinase (MEK), and MAPK-activated protein kinase-2 (MK2). The assay operates in a 96-well format and specifically measures endogenous kinase activation with coefficients of variation less than 20%. Multiplex tracking of kinase-substrate pairs reduces input requirements by 25-fold, with ~75 µg of cellular extract sufficient for fiveplex activity profiling. We applied the assay to monitor kinase signaling during coxsackievirus B3 infection of two different host-cell types and identified multiple differences in pathway dynamics and coordination that warrant future study. Because the Akt–IKK–JNK–MEK–MK2 pathways regulate many important cellular functions, the fiveplex assay should find applications in inflammation, environmental-stress, and cancer research.

scholarly journals The major phosphorylation site of the NADPH oxidase component p67phox is Thr233

1999 ◽  
Vol 338 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Louisa V. FORBES ◽  
Oanh TRUONG ◽  
Frans B. WIENTJES ◽  
Stephen J. MOSS ◽  
Anthony W. SEGAL
Keyword(s):  
Protein Kinase ◽  
Cyanogen Bromide ◽  
Tryptic Peptide ◽  
Phosphorylation Site ◽  
Mitogen Activated Protein Kinase ◽  
Rich Domain ◽  
Mitogen Activated Protein ◽  
Phosphopeptide Mapping ◽  
Major Phosphorylation Site

Phosphorylation of p67phox was shown to increase two- to three-fold upon stimulation by PMA, N-formylmethionyl-leucylphenylalanine or serum-opsonized zymosan. Phosphopeptide mapping showed one major tryptic peptide for p67phox immunoprecipitated from resting or stimulated cells. In vitro phosphorylation of p67phox by isolated cytosol or mitogen-activated protein kinase also generated the same phosphopeptide. Results of cyanogen bromide digestion and HPLC–MS suggested that Thr233 was the phosphorylated residue. Mutagenesis of Thr233 to alanine resulted in loss of phosphorylation in vitro. In the present work, Thr233 has been identified as the major phosphorylation site of p67phox, which is situated in a proline-rich domain.

scholarly journals Synthetic dysmobility screen unveils an integrated STK40-YAP-MAPK system driving cell migration

2021 ◽  
Author(s):  
Ling-Yea Yu ◽  
Ting-Jen Tseng ◽  
Hsuan-Chao Lin ◽  
Ting-Xuan Lu ◽  
Chia-Jung Tsai ◽  
...  
Keyword(s):  
Cell Migration ◽  
Focal Adhesion ◽  
Synthetic Lethality ◽  
Control Cell ◽  
Mitogen Activated Protein Kinase ◽  
Serine Threonine Kinase ◽  
Threonine Kinase ◽  
Mitogen Activated Protein ◽  
Novel Strategy ◽  
Migration Of Cells

AbstractIntegrating signals is essential for cell survival, leading to the concept of synthetic lethality. However, how signaling is integrated to control cell migration remains unclear. By conducting a “two-hit” screen, we revealed the synergistic reduction of cell migration when serine-threonine kinase 40 (STK40) and mitogen-activated protein kinase (MAPK) were simultaneously suppressed. Single-cell analyses showed that STK40 knockdown reduced cell motility and coordination by strengthening focal adhesion (FA) complexes. Furthermore, STK40 knockdown reduced translocation of yes-associated protein (YAP) into the nucleus, while MAPK inhibition further weakened YAP activities in the nucleus to disturb FA remodeling. Altogether, we unveiled an integrated STK40-YAP-MAPK system regulating cell migration, and introduced “synthetic dysmobility” as a novel strategy to collaboratively control cell migration.One Sentence SummaryBlocking collaborative pathways within the integrated signaling network synergistically disrupts the migration of cells.

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