scholarly journals The scaffolding protein Cnk Interacts with Alk to Promote Visceral Founder Cell Specification in Drosophila

2017 ◽  
Author(s):  
Georg Wolfstetter ◽  
Kathrin Pfeifer ◽  
Jesper Ruben van Dijk ◽  
Fredrik Hugosson ◽  
Xiangyi Lu ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Essential Role ◽  
Ectopic Expression ◽  
Scaffolding Protein ◽  
Binding Motif ◽  
Cell Specification ◽  
Visceral Mesoderm

ABSTRACTIn Drosophila, the receptor tyrosine kinase Alk and its ligand Jeb are required to drive founder cell (FC) specification in the visceral mesoderm (VM). Alk-signalling activates downstream MAPK/ERK- and PI3K-pathways in human and Drosophila but little is known about immediate downstream signalling events. Here we report that the scaffolding protein Cnk interacts directly with Alk via a novel c-terminal binding motif. Cnk is required for Alk-signalling as ectopic expression of the minimal interaction motif as well as loss of maternal and zygotic cnk blocks visceral FC-formation, resembling the phenotype of jeb and Alk mutants. We also show that the Cnk-interactor Aveugle/Hyphen (Ave/HYP) is critical, while the (pseudo-) kinase Ksr is not required for Alk-signalling in the developing VM. Taken together, Cnk and Ave represent the first molecules downstream of Alk whose loss genocopies the lack of visceral FC-specification of Alk and jeb mutants indicating an essential role in Alk-signalling.

scholarly journals The scaffolding protein Cnk binds to the receptor tyrosine kinase Alk to promote visceral founder cell specification inDrosophila

2017 ◽  
Vol 10 (502) ◽  
pp. eaan0804
Author(s):  
Georg Wolfstetter ◽  
Kathrin Pfeifer ◽  
Jesper R. van Dijk ◽  
Fredrik Hugosson ◽  
Xiangyi Lu ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Scaffolding Protein ◽  
Cell Specification

scholarly journals TRIM31 facilitates K27-linked polyubiquitination of SYK to regulate antifungal immunity

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Xueer Wang ◽  
Honghai Zhang ◽  
Zhugui Shao ◽  
Wanxin Zhuang ◽  
Chao Sui ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Fungal Pathogen ◽  
Essential Role ◽  
Molecular Mechanisms ◽  
Systemic Infection ◽  
Lectin Receptors ◽  
Innate And Adaptive Immunity ◽  
Cytokines And Chemokines

AbstractSpleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase, which plays an essential role in both innate and adaptive immunity. However, the key molecular mechanisms that regulate SYK activity are poorly understood. Here we identified the E3 ligase TRIM31 as a crucial regulator of SYK activation. We found that TRIM31 interacted with SYK and catalyzed K27-linked polyubiquitination at Lys375 and Lys517 of SYK. This K27-linked polyubiquitination of SYK promoted its plasma membrane translocation and binding with the C-type lectin receptors (CLRs), and also prevented the interaction with the phosphatase SHP-1. Therefore, deficiency of Trim31 in bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs) dampened SYK-mediated signaling and inhibited the secretion of proinflammatory cytokines and chemokines against the fungal pathogen Candida albicans infection. Trim31−/− mice were also more sensitive to C. albicans systemic infection than Trim31+/+ mice and exhibited reduced Th1 and Th17 responses. Overall, our study uncovered the pivotal role of TRIM31-mediated K27-linked polyubiquitination on SYK activation and highlighted the significance of TRIM31 in anti-C. albicans immunity.

scholarly journals EphB1 in Endothelial Cells Regulates Caveolae Formation and Endocytosis

2019 ◽  
Author(s):  
Chinnaswamy Tiruppathi ◽  
Sushil C. Regmi ◽  
Dong-Mei Wang ◽  
Gary C.H. Mo ◽  
Peter T. Toth ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Binding Motif ◽  
Caveolin 1 ◽  
Lung Vessels ◽  
Native Ligand

AbstractCaveolae, the cave-like structures abundant in endothelial cells (ECs), are important in regulating key functions such as caveolae-mediated endocytosis and generation of nitric oxide. Here we show that deletion of the receptor tyrosine kinase EphB1 (EphB1−/−) in mice markedly reduced the caveolae number in ECs of heart and lung vessels and prevented caveolae-mediated endocytosis. EphB1 expressed in adult ECs was shown to bind the caveolin-1 (Cav-1) scaffold domain (CSD) via the CSD binding motif (CSDBM) on EphB1. We demonstrated that activation of EphB1 by the native ligand Ephrin B1 uncoupled EphB1 from Cav-1, and licensed Src-dependent Y-14 Cav-1 phosphorylation. Deletion of CSDBM on EphB1 prevented EphB1/Cav-1 interaction and the activation of Src and Src mediated Y-14 Cav-1 phosphorylation. These studies identify the central role of endothelium expressed EphB1 in regulating caveolae biogenesis and caveolae-mediated endocytosis.

Ectopic expression of seven-up causes cell fate changes during ommatidial assembly

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1123-1135 ◽  
Author(s):  
Y. Hiromi ◽  
M. Mlodzik ◽  
S.R. West ◽  
G.M. Rubin ◽  
C.S. Goodman
Keyword(s):  
Cell Fate ◽  
Receptor Tyrosine Kinase ◽  
Essential Role ◽  
Ectopic Expression ◽  
Spatiotemporal Pattern ◽  
Morphogenetic Furrow ◽  
Cellular Origin ◽  
Cone Cells ◽  
Sevenless Receptor Tyrosine Kinase ◽  
Photoreceptor Neurons

During Drosophila ommatidial development, a single cell is selected within the ommatidial cluster to become the R7 photoreceptor neuron. The seven-up gene has been shown to play a role in this process by preventing four other photoreceptor precursors, R3/R4/R1/R6, from adopting the R7 cell fate. The seven-up gene encodes a steroid receptor-like molecule that is expressed only in those four cells that require seven-up function in the developing Drosophila ommatidium. We have examined the functional significance of the spatially restricted expression of seven-up by misexpressing seven-up isoforms. As expected from the function that seven-up performs in R3/R4/R1/R6, ubiquitous expression of seven-up causes transformation of the R7 cell to an R1-R6 cell fate. In addition, depending on the timing and spatial pattern of expression, various other phenotypes are produced including the loss of the R7 cell and the formation of extra R7 cells. Ubiquitous expression of seven-up close to the morphogenetic furrow interferes with R8 differentiation resulting in failure to express the boss protein, the ligand for the sevenless receptor tyrosine kinase, and the R7 cell is lost consequently. Extra R7 cells are formed by recruiting non-neuronal cone cells as photoreceptor neurons in a sevenless and bride of sevenless independent way. Thus, the spatiotemporal pattern of seven-up expression plays an essential role in controlling the number and cellular origin of the R7 neuron in the ommatidium. Our results also suggest that seven-up controls decisions not only between photoreceptor subtypes, but also between neuronal and non-neuronal fates.

scholarly journals Exome Sequencing Defines the Molecular Pathogenesis of Vein of Galen Malformation

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Adam Kundishora ◽  
Xue Zeng ◽  
Daniel Duran ◽  
August A Allocco ◽  
Jungmin Choi ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
De Novo ◽  
Exome Capture ◽  
Binding Motif ◽  
Vein Of Galen ◽  
Eph Receptor ◽  
Fold Enrichment ◽  
Significant Enrichment ◽  
New Gene

Abstract INTRODUCTION Vein of Galen malformations (VOGMs) are morbid arteriovenous malformations, with poorly described genetis. 1 Despite improvement in endovascular treatment, VOGM mortality remains high. 2 VOGM has been reported as a rare finding in Capillary Malformation-Arteriovenous Malformation Syndrome (RASA1; OMIM #605384) and Hereditary Hemorrhagic Telangiectasia (ENG, ACVRL1; OMIM #187300, #600376). 3-4 Our previous work has identified EPH receptor tyrosine kinase as also playing a role in VOGM pathogenesis. 5 Here, we report a larger cohort of probands and identify a new gene in the same pathway as EPHB4 as playing a role in VOGM. METHODS Germline DNA was isolated from 84 unrelated probands harboring radiographically confirmed VOGMs Both parents were available for 69/84 probands. Exome capture and paired-end WES was performed on DNA samples from participating individuals (n = 237). Data was bioinformatically analyzed to identify rare de-novo and transmitted mutations. Binomial analysis tested for exome-wide significance of mutational burden. RESULTS Only 3/75 patients harbored mutations in previously reported VOGM-associated genes (2.3%; RASA1 n = 2, 1.1%; ACVRL1 n = 1). Significant enrichment of rare damaging mutations was found for a member of the EPH receptor tyrosine kinase family (EPHB4, n = 5; 6.0%; P = 3.31 × 10–7, 36.62-fold enrichment). Entirely novel mutations in the integrin family were also identified (n = 2; 1.1%, P = 6.03 × 10–5, 179.6-fold enrichment). Both of these mutations are located in the c-terminal domain and disrupt a binding motif. Furthermore, this integrin protein mutation is involved in the same pathway as EPHB4, although whether or not they directly interact remains unknown. CONCLUSION This work represents an expansion upon the largest phenotyped, exome-sequenced VOGM cohort in the world. Having discovered a new gene in the same pathway as EPHB4 strongly implicates said pathway in VOMG development. We are currently pioneering tissue sampling from endovascular instruments used during treatment to explore potential somatic mutations. Our findings continue to uncover genetic determinants of VOGM pathogenesis, providing novel insight into vascular developmental biology.

scholarly journals Increasing the Receptor Tyrosine Kinase EphB2 Prevents Amyloid-β-induced Depletion of Cell Surface Glutamate Receptors by a Mechanism That Requires the PDZ-binding Motif of EphB2 and Neuronal Activity

2015 ◽  
Vol 291 (4) ◽  
pp. 1719-1734 ◽  
Author(s):  
Takashi Miyamoto ◽  
Daniel Kim ◽  
Joseph A. Knox ◽  
Erik Johnson ◽  
Lennart Mucke
Keyword(s):  
Tyrosine Kinase ◽  
Protective Effect ◽  
Glutamate Receptors ◽  
Neuronal Activity ◽  
Receptor Tyrosine Kinase ◽  
Neurodegenerative Disorder ◽  
Pdz Domain ◽  
Amyloid Β ◽  
Neuronal Cultures ◽  
Binding Motif

Diverse lines of evidence suggest that amyloid-β (Aβ) peptides causally contribute to the pathogenesis of Alzheimer disease (AD), the most frequent neurodegenerative disorder. However, the mechanisms by which Aβ impairs neuronal functions remain to be fully elucidated. Previous studies showed that soluble Aβ oligomers interfere with synaptic functions by depleting NMDA-type glutamate receptors (NMDARs) from the neuronal surface and that overexpression of the receptor tyrosine kinase EphB2 can counteract this process. Through pharmacological treatments and biochemical analyses of primary neuronal cultures expressing wild-type or mutant forms of EphB2, we demonstrate that this protective effect of EphB2 depends on its PDZ-binding motif and the presence of neuronal activity but not on its kinase activity. We further present evidence that the protective effect of EphB2 may be mediated by the AMPA-type glutamate receptor subunit GluA2, which can become associated with the PDZ-binding motif of EphB2 through PDZ domain-containing proteins and can promote the retention of NMDARs in the membrane. In addition, we show that the Aβ-induced depletion of surface NMDARs does not depend on several factors that have been implicated in the pathogenesis of Aβ-induced neuronal dysfunction, including aberrant neuronal activity, tau, prion protein (PrPC), and EphB2 itself. Thus, although EphB2 does not appear to be directly involved in the Aβ-induced depletion of NMDARs, increasing its expression may counteract this pathogenic process through a neuronal activity- and PDZ-dependent regulation of AMPA-type glutamate receptors.

scholarly journals A Novel Stat3 Binding Motif in Gab2 Mediates Transformation of Primary Hematopoietic Cells by the Stk/Ron Receptor Tyrosine Kinase in Response to Friend Virus Infection

2007 ◽  
Vol 27 (10) ◽  
pp. 3708-3715 ◽  
Author(s):  
Shuang Ni ◽  
Chunmei Zhao ◽  
Gen-Sheng Feng ◽  
Robert F. Paulson ◽  
Pamela H. Correll
Keyword(s):  
Tyrosine Kinase ◽  
Binding Site ◽  
Receptor Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Binding Motif ◽  
Friend Virus ◽  
Erythroid Progenitor ◽  
Ron Receptor ◽  
Infected Cells

ABSTRACT Friend erythroleukemia virus has long served as a paradigm for the study of the multistage progression of leukemia. Friend virus infects erythroid progenitor cells, followed by an initial polyclonal expansion of infected cells, which is driven by the activation of a naturally occurring truncated form of the Stk receptor tyrosine kinase (Sf-Stk). Subsequently, the accumulation of additional mutations in p53 and the activation of PU.1 result in full leukemic transformation. The early stages of transformation induced by Friend virus are characterized in vitro by the Epo-independent growth of infected erythroblasts. We have shown previously that this transforming event requires the kinase activity and Grb2 binding site of Sf-Stk and the recruitment of a Grb2/Gab2 complex to Sf-Stk. Here, we demonstrate that Stat3 is required for the Epo-independent growth of Friend virus-infected cells and that the activation of Stat3 by Sf-Stk is mediated by a novel Stat3 binding site in Gab2. These results underscore a central role for Stat3 in hematopoietic transformation and describe a previously unidentified role for Gab2 in the recruitment and activation of Stat3 in response to transforming signals generated by tyrosine kinases.

scholarly journals Phosphotyrosine 1062 Is Critical for the In Vivo Activity of the Ret9 Receptor Tyrosine Kinase Isoform

2005 ◽  
Vol 25 (21) ◽  
pp. 9661-9673 ◽  
Author(s):  
Adrianne Wong ◽  
Silvia Bogni ◽  
Pille Kotka ◽  
Esther de Graaff ◽  
Vivette D'Agati ◽  
...  
Keyword(s):  
Nervous System ◽  
Amino Acid ◽  
Tyrosine Kinase ◽  
Enteric Nervous System ◽  
Receptor Tyrosine Kinase ◽  
System Development ◽  
Critical Role ◽  
Nervous System Development ◽  
Binding Motif

ABSTRACT The receptor tyrosine kinase Ret plays a critical role in the development of the mammalian excretory and enteric nervous systems. Differential splicing of the primary Ret transcript results in the generation of two main isoforms, Ret9 and Ret51, whose C-terminal amino acid tails diverge after tyrosine (Y) 1062. Monoisoformic mice expressing only Ret9 develop normally and are healthy and fertile. In contrast, animals expressing only Ret51 have aganglionosis of the distal gut and hypoplastic kidneys. By generating monoisoformic mice in which Y1062 of Ret9 has been mutated to phenylalanine, we demonstrate that this amino acid has a critical role in Ret9 signaling that is necessary for the development of the kidneys and the enteric nervous system. These findings argue that the distinct activities of Ret9 and Ret51 result from the differential regulation of Y1062 by C-terminal flanking sequences. However, a mutation which places Y1062 of Ret51 in a Ret9 context improves only marginally the ability of Ret51 to support renal and enteric nervous system development. Finally, monoisoformic mice expressing a variant of Ret9 in which a C-terminal PDZ-binding motif was mutated develop normally and are healthy. Our studies identify Y1062 as a critical regulator of Ret9 signaling and suggest that Ret51-specific motifs are likely to inhibit the activity of this isoform.

Ectopic Expression of Mer Receptor Tyrosine Kinase in Childhood T Cell Acute Lymphoblastic Leukemia.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4310-4310
Author(s):  
Dana B. Salzberg ◽  
Amy K. Keating ◽  
Jian-zhe Cao ◽  
Susan Sather ◽  
Kimberley Hill ◽  
...  
Keyword(s):  
Acute Lymphoblastic Leukemia ◽  
T Cell ◽  
Tyrosine Kinase ◽  
Cell Lines ◽  
Receptor Tyrosine Kinase ◽  
Lymphoblastic Leukemia ◽  
Ectopic Expression ◽  
Surface Expression ◽  
Protein Surface ◽  
Sample Number

Abstract Tyrosine kinases play an important role in normal cellular growth and differentiation. Deregulation of tyrosine kinase activity can result in cellular transformation leading to the development of human cancer. The Mer receptor tyrosine kinase, initially cloned from a human B lymphoblastoid cell line, is expressed in a spectrum of hematopoetic, epithelial, and mesenchymal cell lines. Interestingly, while the RNA transcript of Mer is detected in numerous T and B lymphoblastic cell lines, Mer RNA is not found in normal human thymocytes, lymphocytes or in PMA/PHA stimulated lymphocytes. We have developed an anti-human Mer monoclonal antibody to further study the ectopic Mer expression in lymphoblasts. The antibody detects several forms of the Mer protein including a fully glycosylated 205 kD Mer protein in monocytes and a less glycosylated 170–180 kD Mer protein in acute lymphoblastic leukemia (ALL) cell lines. We analyzed lymphoblasts from 16 T cell ALL patients diagnosed between July 1995 and July 2004 at The Children’s Hospital, Denver for Mer protein surface expression. Of the T cell ALL patient samples, we found that 9/16 (56%) were positive for Mer protein surface expression. Although we were not able to statistically evaluate the clinical outcomes relative to Mer expression due to the study sample number, there was a statistically significant association between positive expression of Mer and lack of surface expression of CD3 (p = 0.035). We found that 7/9 (78%) of the Mer positive lymphoblasts lacked CD3 surface expression, while only 1/6 (17%) of the Mer negative samples lacked CD3 surface expression (see figure). Lymphoblasts that lack surface expression of CD3 represent an immature phenotype and have been associated with a decreased event free survival as compared with surface positive CD3 lymphoblasts. Further investigation of the ectopic expression of Mer in lymphoblasts may reveal the use of this novel Mer glycosylated protein as a prognostic marker and possibly a future therapeutic target in the treatment of childhood leukemia. Figure Figure

Sign in / Sign up

Export Citation Format

Share Document