scholarly journals Melanocyte transformation requires complete loss of all pocket protein function via a mechanism that mitigates the need for MAPK pathway activation

Oncogene ◽  
2017 ◽  
Vol 36 (26) ◽  
pp. 3789-3795 ◽  
Author(s):  
I D Tonks ◽  
P Mukhopadhyay ◽  
W A Schroder ◽  
A Sorolla ◽  
A W Mould ◽  
...  
Keyword(s):  
Protein Function ◽  
Mapk Pathway ◽  
Complete Loss ◽  
Pocket Protein ◽  
Pathway Activation

scholarly journals Mutant SETBP1 enhances NRAS-driven MAPK pathway activation to promote aggressive leukemia

Leukemia ◽  
2021 ◽  
Author(s):  
Sarah A. Carratt ◽  
Theodore P. Braun ◽  
Cody Coblentz ◽  
Zachary Schonrock ◽  
Rowan Callahan ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Pathway Activation

scholarly journals trans-Fatty acids promote p53-dependent apoptosis triggered by cisplatin-induced DNA interstrand crosslinks via the Nox-RIP1-ASK1-MAPK pathway

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yusuke Hirata ◽  
Miki Takahashi ◽  
Yuto Yamada ◽  
Ryosuke Matsui ◽  
Aya Inoue ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mapk Pathway ◽  
Regulatory Protein ◽  
Strand Break ◽  
Mitogen Activated Protein Kinase ◽  
Ros Generation ◽  
Apoptotic Pathway ◽  
Interstrand Crosslinks ◽  
Pathway Activation ◽  
Dna Interstrand Crosslinks

Abstracttrans-Fatty acids (TFAs) are food-derived fatty acids associated with various diseases including cardiovascular diseases. However, the underlying etiology is poorly understood. Here, we show a pro-apoptotic mechanism of TFAs such as elaidic acid (EA), in response to DNA interstrand crosslinks (ICLs) induced by cisplatin (CDDP). We previously reported that TFAs promote apoptosis induced by doxorubicin (Dox), a double strand break (DSB)-inducing agent, via a non-canonical apoptotic pathway independent of tumor suppressor p53 and apoptosis signal-regulating kinase (ASK1), a reactive oxygen species (ROS)-responsive kinase. However, here we found that in the case of CDDP-induced apoptosis, EA-mediated pro-apoptotic action was reversed by knockout of either p53 or ASK1, despite no increase in p53 apoptotic activity. Upon CDDP treatment, EA predominantly enhanced ROS generation, ASK1-p38/c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathway activation, and ultimately cell death, all of which were suppressed either by co-treatment of the NADPH oxidase (Nox) inhibitor Apocynin, or by knocking out its regulatory protein, receptor-interacting protein 1 (RIP1). These results demonstrate that in response to CDDP ICLs, TFAs promote p53-dependent apoptosis through the enhancement of the Nox-RIP1-ASK1-MAPK pathway activation, providing insight into the diverse pathogenetic mechanisms of TFAs according to the types of DNA damage.

scholarly journals Molecular characterisation of rare loss-of-function NPAS3 and NPAS4 variants identified in individuals with neurodevelopmental disorders

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph J. Rossi ◽  
Jill A. Rosenfeld ◽  
Katie M. Chan ◽  
Haley Streff ◽  
Victoria Nankivell ◽  
...  
Keyword(s):  
Neurodevelopmental Disorders ◽  
Protein Function ◽  
Transcriptional Activity ◽  
Neurodevelopmental Disorder ◽  
Complete Loss ◽  
Loss Of Function ◽  
Targeted Disruption ◽  
Clinical Exome Sequencing ◽  
Partner Protein ◽  
The Brain

AbstractAberrations in the excitatory/inhibitory balance within the brain have been associated with both intellectual disability (ID) and schizophrenia (SZ). The bHLH-PAS transcription factors NPAS3 and NPAS4 have been implicated in controlling the excitatory/inhibitory balance, and targeted disruption of either gene in mice results in a phenotype resembling ID and SZ. However, there are few human variants in NPAS3 and none in NPAS4 that have been associated with schizophrenia or neurodevelopmental disorders. From a clinical exome sequencing database we identified three NPAS3 variants and four NPAS4 variants that could potentially disrupt protein function in individuals with either developmental delay or ID. The transcriptional activity of the variants when partnered with either ARNT or ARNT2 was assessed by reporter gene activity and it was found that variants which truncated the NPAS3/4 protein resulted in a complete loss of transcriptional activity. The ability of loss-of-function variants to heterodimerise with neuronally enriched partner protein ARNT2 was then determined by co-immunoprecipitation experiments. It was determined that the mechanism for the observed loss of function was the inability of the truncated NPAS3/4 protein to heterodimerise with ARNT2. This further establishes NPAS3 and NPAS4 as candidate neurodevelopmental disorder genes.

scholarly journals BRAFDuplications and MAPK Pathway Activation Are Frequent in Gliomas of the Optic Nerve Proper

2012 ◽  
Vol 71 (9) ◽  
pp. 789-795 ◽  
Author(s):  
Fausto J. Rodriguez ◽  
Azra H. Ligon ◽  
Iren Horkayne-Szakaly ◽  
Elisabeth J. Rushing ◽  
Keith L. Ligon ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Mapk Pathway ◽  
Pathway Activation

scholarly journals Activating mutations in BRAF disrupt the hypothalamo-pituitary axis leading to hypopituitarism in mice and humans

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Angelica Gualtieri ◽  
Nikolina Kyprianou ◽  
Louise C. Gregory ◽  
Maria Lillina Vignola ◽  
James G. Nicholson ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Critical Role ◽  
Cell Lineage ◽  
Activating Mutations ◽  
Pathway Activation ◽  
Tumour Formation ◽  
Conditional Expression ◽  
Cell Cycle Inhibitors ◽  
Mutation Braf

AbstractGermline mutations in BRAF and other components of the MAPK pathway are associated with the congenital syndromes collectively known as RASopathies. Here, we report the association of Septo-Optic Dysplasia (SOD) including hypopituitarism and Cardio-Facio-Cutaneous (CFC) syndrome in patients harbouring mutations in BRAF. Phosphoproteomic analyses demonstrate that these genetic variants are gain-of-function mutations leading to activation of the MAPK pathway. Activation of the MAPK pathway by conditional expression of the BrafV600E/+ allele, or the knock-in BrafQ241R/+ allele (corresponding to the most frequent human CFC-causing mutation, BRAF p.Q257R), leads to abnormal cell lineage determination and terminal differentiation of hormone-producing cells, causing hypopituitarism. Expression of the BrafV600E/+ allele in embryonic pituitary progenitors leads to an increased expression of cell cycle inhibitors, cell growth arrest and apoptosis, but not tumour formation. Our findings show a critical role of BRAF in hypothalamo-pituitary-axis development both in mouse and human and implicate mutations found in RASopathies as a cause of endocrine deficiencies in humans.

Oncogenic FAM131B–BRAF fusion resulting from 7q34 deletion comprises an alternative mechanism of MAPK pathway activation in pilocytic astrocytoma

2011 ◽  
Vol 121 (6) ◽  
pp. 763-774 ◽  
Author(s):  
Huriye Cin ◽  
Claus Meyer ◽  
Ricarda Herr ◽  
Wibke G. Janzarik ◽  
Sally Lambert ◽  
...  
Keyword(s):  
Pilocytic Astrocytoma ◽  
Mapk Pathway ◽  
Alternative Mechanism ◽  
Pathway Activation ◽  
Braf Fusion

Molecular characterization of the Ras-MAPK pathway in metastatic breast cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 1034-1034
Author(s):  
Justin Wayne Wong Tiu-lim ◽  
Jun Yin ◽  
Joanne Xiu ◽  
Wolfgang Michael Korn ◽  
Heinz-Josef Lenz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Mapk Pathway ◽  
Metastatic Breast ◽  
Molecular Alterations ◽  
Ras Genes ◽  
Mutational Status ◽  
Pathway Activation ◽  
Class 1

1034 Background: The Ras-MAPK pathway is a known driver of tumorigenesis and therapeutic target in a variety of cancers. Alterations in this pathway have been linked to decreased tumor immunogenicity. However, molecular alterations in the Ras-MAPK are rare in breast cancer (BC) and their clinical implications remain unclear. As mutational status does not accurately correlate with transcriptional activity, a MAPK pathway activity score (MPAS, Wagle et al., 2018, npj Precision Medicine) is indicative of MAPK activation and correlates with response to MEK (MEKi) or BRAF inhibition (BRAFi). Our goal was to determine the frequency of molecular alterations in the Ras-MAPK and correlate to MAPK pathway activation in MBC. Methods: A total of 6464 BC samples underwent comprehensive molecular profiling at Caris Life Sciences. Analyses included next generation sequencing of DNA (592 Gene Panel, NextSeq; whole exome sequencing, NovaSEQ), RNA (NovaSeq, whole transcriptome sequencing, WTS) and IHC. MPAS and immune cell fraction (ICF, Quantiseq) were assessed by mRNA analysis. Wilcoxon, Fisher’s exact, or Dunnett’s test was used. All results shown were statistically significant (p < 0.05). Results: The predominant alteration of RAS genes was mutation followed by amplification, no fusions were detected (Table). Only 0.17% of all tumors harbor KRAS G12c mutations. The highest MPAS scores were found in KRAS mutants (mut), HRAS mut (Q61, G1213), BRAF V600 (class 1) mut and NRAS Q61 mut (Table) and therefore used to define Genomic MAPK Activated Tumors (GMAT). GMAT compared to wild type (WT) had significantly higher PD-L1 expression, TMB and MSI/dMMR. GMAT had less B cells (3.4% vs 4.4%), more M1 Macrophages (4.4% vs 3.4%) and neutrophils (5.5% vs 2.7%) regardless of HR status but less NK cells (2.3% s 3.0%), MSDCs (0.9% vs 3.0%) only in HR- tumors with respect to WT. GMAT tumors showed more frequent mutation rate (mr) of PIK3CA (HR+: 57.3% vs 40%; HR-: 41.9% vs 17.9%). HR+ tumors had a higher mr of MSH3 (11.8% vs 0.6%) while HR- tumors had higher mr of PIK3R1 (9.6% vs 3.8%), RhoA (5.3% vs 0.5%), DNA repair genes (TERT, 18.2% vs 1.0%; ARID1A, 18.2% vs 5.9%; PRKDC, 3.9% vs 0) and lower TP53 mr (54.5% vs 85.8%) compared to WT. Conclusions: Our study demonstrates that RAS, BRAF and MEK1 mutations are associated with MAPK pathway activation indicative of benefit from MEKi or BRAFi. GMAT warrant further investigation for combinations targeting the RAS-MAPK pathway and immune checkpoint inhibitors.[Table: see text]

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