scholarly journals A novel pH-dependent membrane peptide that binds to EphA2 and inhibits cell migration

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Daiane S Alves ◽  
Justin M Westerfield ◽  
Xiaojun Shi ◽  
Vanessa P Nguyen ◽  
Katherine M Stefanski ◽  
...  
Keyword(s):  
Cell Migration ◽  
Receptor Tyrosine Kinase ◽  
Lipid Membranes ◽  
Transmembrane Domain ◽  
Activation Mechanism ◽  
Extracellular Medium ◽  
Akt Phosphorylation ◽  
Signaling Axis ◽  
Membrane Peptide ◽  
Ph Dependent

Misregulation of the signaling axis formed by the receptor tyrosine kinase (RTK) EphA2 and its ligand, ephrinA1, causes aberrant cell-cell contacts that contribute to metastasis. Solid tumors are characterized by an acidic extracellular medium. We intend to take advantage of this tumor feature to design new molecules that specifically target tumors. We created a novel pH-dependent transmembrane peptide, TYPE7, by altering the sequence of the transmembrane domain of EphA2. TYPE7 is highly soluble and interacts with the surface of lipid membranes at neutral pH, while acidity triggers transmembrane insertion. TYPE7 binds to endogenous EphA2 and reduces Akt phosphorylation and cell migration as effectively as ephrinA1. Interestingly, we found large differences in juxtamembrane tyrosine phosphorylation and the extent of EphA2 clustering when comparing TYPE7 with activation by ephrinA1. This work shows that it is possible to design new pH-triggered membrane peptides to activate RTK and gain insights on its activation mechanism.

scholarly journals Author response: A novel pH-dependent membrane peptide that binds to EphA2 and inhibits cell migration

2018 ◽  
Author(s):  
Daiane S Alves ◽  
Justin M Westerfield ◽  
Xiaojun Shi ◽  
Vanessa P Nguyen ◽  
Katherine M Stefanski ◽  
...  
Keyword(s):  
Cell Migration ◽  
Author Response ◽  
Membrane Peptide ◽  
Ph Dependent

scholarly journals Two protonation switches control rhodopsin activation in membranes

2008 ◽  
Vol 105 (46) ◽  
pp. 17795-17800 ◽  
Author(s):  
Mohana Mahalingam ◽  
Karina Martínez-Mayorga ◽  
Michael F. Brown ◽  
Reiner Vogel
Keyword(s):  
Transmembrane Domain ◽  
Conformational Transition ◽  
Salt Bridge ◽  
Receptor Activation ◽  
Activation Mechanism ◽  
Partial Activation ◽  
Ph Dependent ◽  
G Protein Coupled ◽  
Receptor Conformation ◽  
Receptor Family

Activation of the G protein-coupled receptor (GPCR) rhodopsin is initiated by light-induced isomerization of the retinal ligand, which triggers 2 protonation switches in the conformational transition to the active receptor state Meta II. The first switch involves disruption of an interhelical salt bridge by internal proton transfer from the retinal protonated Schiff base (PSB) to its counterion, Glu-113, in the transmembrane domain. The second switch consists of uptake of a proton from the solvent by Glu-134 of the conserved E(D)RY motif at the cytoplasmic terminus of helix 3, leading to pH-dependent receptor activation. By using a combination of UV–visible and FTIR spectroscopy, we study the activation mechanism of rhodopsin in different membrane environments and show that these 2 protonation switches become partially uncoupled at physiological temperature. This partial uncoupling leads to ≈50% population of an entropy-stabilized Meta II state in which the interhelical PSB salt bridge is broken and activating helix movements have taken place but in which Glu-134 remains unprotonated. This partial activation is converted to full activation only by coupling to the pH-dependent protonation of Glu-134 from the solvent, which stabilizes the active receptor conformation by lowering its enthalpy. In a membrane environment, protonation of Glu-134 is therefore a thermodynamic rather than a structural prerequisite for activating helix movements. In light of the conservation of the E(D)RY motif in rhodopsin-like GPCRs, protonation of this carboxylate also may serve a similar function in signal transduction of other members of this receptor family.

scholarly journals Spatial Structure and pH-dependent Conformational Diversity of Dimeric Transmembrane Domain of the Receptor Tyrosine Kinase EphA1

2008 ◽  
Vol 283 (43) ◽  
pp. 29385-29395 ◽  
Author(s):  
Eduard V. Bocharov ◽  
Maxim L. Mayzel ◽  
Pavel E. Volynsky ◽  
Marina V. Goncharuk ◽  
Yaroslav S. Ermolyuk ◽  
...  
Keyword(s):  
Spatial Structure ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Transmembrane Domain ◽  
Conformational Diversity ◽  
Ph Dependent

scholarly journals Collagen induces activation of DDR1 through lateral dimer association and phosphorylation between dimers

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Victoria Juskaite ◽  
David S Corcoran ◽  
Birgit Leitinger
Keyword(s):  
Receptor Tyrosine Kinase ◽  
Drug Target ◽  
Kinase Activity ◽  
Transmembrane Domain ◽  
Activation Mechanism ◽  
Collagen Binding ◽  
Wide Range ◽  
Different Types ◽  
In Trans ◽  
Discoidin Domain Receptor 1

The collagen-binding receptor tyrosine kinase DDR1 (discoidin domain receptor 1) is a drug target for a wide range of human diseases, but the molecular mechanism of DDR1 activation is poorly defined. Here we co-expressed different types of signalling-incompetent DDR1 mutants (‘receiver’) with functional DDR1 (‘donor’) and demonstrate phosphorylation of receiver DDR1 by donor DDR1 in response to collagen. Making use of enforced covalent DDR1 dimerisation, which does not affect receptor function, we show that receiver dimers are phosphorylated in trans by the donor; this process requires the kinase activity of the donor but not that of the receiver. The receiver ectodomain is not required, but phosphorylation in trans is abolished by mutation of the transmembrane domain. Finally, we show that mutant DDR1 that cannot bind collagen is recruited into DDR1 signalling clusters. Our results support an activation mechanism whereby collagen induces lateral association of DDR1 dimers and phosphorylation between dimers.

scholarly journals A Novel Membrane Peptide that Inhibits Cell Migration by Activation of the Receptor Tyrosine Kinase EphA2

2018 ◽  
Vol 114 (3) ◽  
pp. 265a
Author(s):  
Justin M. Westerfield ◽  
Daiane S. Alves ◽  
Xiaojun Shi ◽  
Vanessa P. Nguyen ◽  
Robert H. Pullen ◽  
...  
Keyword(s):  
Cell Migration ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Membrane Peptide

scholarly journals EphA2 and EGFR: Friends in Life, Partners in Crime. Can EphA2 Be a Predictive Biomarker of Response to Anti-EGFR Agents?

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 700
Author(s):  
Mario Cioce ◽  
Vito Michele Fazio
Keyword(s):  
Colorectal Cancer ◽  
Solid Tumors ◽  
Receptor Tyrosine Kinase ◽  
Predictive Biomarker ◽  
Eph Receptors ◽  
Oncogenic Signaling ◽  
Induced Stress ◽  
Molecular Determinants ◽  
Signaling Axis ◽  
Context Specific

The Eph receptors represent the largest group among Receptor Tyrosine kinase (RTK) families. The Eph/ephrin signaling axis plays center stage during development, and the deep perturbation of signaling consequent to its dysregulation in cancer reveals the multiplicity and complexity underlying its function. In the last decades, they have emerged as key players in solid tumors, including colorectal cancer (CRC); however, what causes EphA2 to switch between tumor-suppressive and tumor-promoting function is still an active theater of investigation. This review summarizes the recent advances in understanding EphA2 function in cancer, with detail on the molecular determinants of the oncogene-tumor suppressor switch function of EphA2. We describe tumor context-specific examples of EphA2 signaling and the emerging role EphA2 plays in supporting cancer—stem—cell-like populations and overcoming therapy-induced stress. In such a frame, we detail the interaction of the EphA2 and EGFR pathway in solid tumors, including colorectal cancer. We discuss the contribution of the EphA2 oncogenic signaling to the resistance to EGFR blocking agents, including cetuximab and TKIs.

scholarly journals CircSOD2 induced epigenetic alteration drives hepatocellular carcinoma progression through activating JAK2/STAT3 signaling pathway

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Zhongwei Zhao ◽  
Jingjing Song ◽  
Bufu Tang ◽  
Shiji Fang ◽  
Dengke Zhang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Cell Migration ◽  
Real Time ◽  
Signaling Pathway ◽  
Molecular Mechanism ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway ◽  
Signaling Axis

Abstract Background Emerging evidence suggests that circular RNAs play critical roles in disease development especially in cancers. Previous genome-wide RNA-seq studies found that a circular RNA derived from SOD2 gene was highly upregulated in hepatocellular carcinoma (HCC), however, the role of circSOD2 in HCC remains largely unknown. Methods The expression profiling of circSOD2 and microRNA in HCC patients were assessed by Real-Time Quantitative Reverse Transcription PCR (qRT-PCR). SiRNA or CRISPR-CAS9 were used to silence gene expression. The biological function of circSOD2 in HCC was investigated using in vitro and in vivo studies including, trans-well cell migration, cell apoptosis, cell cycle, CCK8, siRNA interference, western blots, and xenograft mouse model. The underlying molecular mechanism was determined by Chromatin Immunoprecipitation quantitative real time PCR (ChIP-qPCR), bioinformatic analysis, biotin-pull down, RNA immunoprecipitation, 5-mc DNA pulldown and luciferase assays. Results In accordance with previous sequencing results, here, we demonstrated that circSOD2 was highly expressed in HCC tumor tissues compared with normal liver tissues. Mechanically, we showed that histone writer EP300 and WDR5 bind to circSOD2 promoter and trigger its promoter H3K27ac and H3K4me3 modification, respectively, which further activates circSOD2 expression. SiRNA mediated circSOD2 suppression impaired liver cancer cell growth, cell migration, prohibited cell cycle progression and in vivo tumor growth. By acting as a sponge, circSOD2 inhibits miR-502-5p expression and rescues miR-502-5p target gene DNMT3a expression. As a DNA methyltransferase, upregulated DNMA3a suppresses SOCS3 expression by increasing SOCS3 promoter DNA methylation. This event further accelerates SOCS3 downstream JAK2/STAT3 signaling pathway activation. In addition, we also found that activated STAT3 regulates circSOD2 expression in a feedback way. Conclusion The novel signaling axis circSOD2/miR-502-5p/DNMT3a/JAK2/STAT3/circSOD2 provides a better understanding of HCC tumorigenesis. The molecular mechanism underlying this signaling axis offers new prevention and treatment of HCC.

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