scholarly journals dDYRK2: a novel dual-specificity tyrosine-phosphorylation-regulated kinase in Drosophila

2003 ◽  
Vol 374 (2) ◽  
pp. 381-391 ◽  
Author(s):  
Pamela A. LOCHHEAD ◽  
Gary SIBBET ◽  
Ross KINSTRIE ◽  
Tava CLEGHON ◽  
Margie RYLATT ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Protein Kinases ◽  
Mutational Analysis ◽  
Kinase Domain ◽  
Activation Loop ◽  
Embryonic Neurogenesis ◽  
Founding Family ◽  
Dual Specificity ◽  
Eukaryotic Organisms

Dual-specificity tyrosine-phosphorylation-regulated kinases (DYRKs) are an emerging family of protein kinases that have been identified in all eukaryotic organisms examined to date. DYRK family members are involved in regulating key developmental and cellular processes such as neurogenesis, cell proliferation, cytokinesis and cellular differentiation. Two distinct subgroups exist, nuclear and cytosolic. In Drosophila, the founding family member minibrain, whose human orthologue maps to the Down syndrome critical region, belongs to the nuclear subclass and affects post-embryonic neurogenesis. In the present paper, we report the isolation of dDYRK2, a cytosolic DYRK and the putative product of the smell-impaired smi35A gene. This is the second such kinase described in Drosophila, but the first to be characterized at the molecular and biochemical level. dDYRK2 is an 81 kDa dual-specificity kinase that autophosphorylates on tyrosine and serine/threonine residues, but appears to phosphorylate exogenous substrates only on serine/threonine residues. It contains a YXY motif in the activation loop of the kinase domain in the same location as the TXY motif in mitogenactivated protein kinases. dDYRK2 is tyrosine-phosphorylated in vivo, and mutational analysis reveals that the activation loop tyrosines are phosphorylated and are essential for kinase activity. Finally, dDYRK2 is active at all stages of fly development, with elevated levels observed during embryogenesis and pupation.

scholarly journals Characterization of Atypical Protein Tyrosine Kinase (PTK) Genes and Their Role in Abiotic Stress Response in Rice

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 664
Author(s):  
Allimuthu Elangovan ◽  
Monika Dalal ◽  
Gopinathan Kumar Krishna ◽  
Sellathdurai Devika ◽  
Ranjeet Ranjan Kumar ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Response ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Rice Genome ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Protein Tyrosine ◽  
Dual Specificity ◽  
Submergence Stress

Tyrosine phosphorylation constitutes up to 5% of the total phophoproteome. However, only limited studies are available on protein tyrosine kinases (PTKs) that catalyze protein tyrosine phosphorylation in plants. In this study, domain analysis of the 27 annotated PTK genes in rice genome led to the identification of 18 PTKs with tyrosine kinase domain. The kinase domain of rice PTKs shared high homology with that of dual specificity kinase BRASSINOSTEROID-INSENSITIVE 1 (BRI1) of Arabidopsis. In phylogenetic analysis, rice PTKs clustered with receptor-like cytoplasmic kinases-VII (RLCKs-VII) of Arabidopsis. mRNAseq analysis using Genevestigator revealed that rice PTKs except PTK9 and PTK16 express at moderate to high level in most tissues. PTK16 expression was highly abundant in panicle at flowering stage. mRNAseq data analysis led to the identification of drought, heat, salt, and submergence stress regulated PTK genes in rice. PTK14 was upregulated under all stresses. qRT-PCR analysis also showed that all PTKs except PTK10 were significantly upregulated in root under osmotic stress. Tissue specificity and abiotic stress mediated differential regulation of PTKs suggest their potential role in development and stress response of rice. The candidate dual specificity PTKs identified in this study paves way for molecular analysis of tyrosine phosphorylation in rice.

Clinical Course and Significance of the Novel FLT3-Y842C Mutation in a Patient with AML Treated with PKC412 Monotherapy.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2537-2537
Author(s):  
T. Kindler ◽  
F. Breitenbuecher ◽  
S. Kasper ◽  
E. Estey ◽  
F. Giles ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Clinical Course ◽  
Novel Mutation ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Activation Loop ◽  
The Novel ◽  
Constitutive Activation

Abstract We recently identified a novel mutation (Y842C) within the tyrosine kinase domain of FLT3 in a patient treated with PKC410 monotherapy (ASH 2003, # 4681). Here, we present follow up studies including the clinical course of the patient and frequency analysis in 110 patients with AML. In addition, we characterized the novel mutation using overexpression of FLT3-Y842C in 32D cells. AML M2 was diagnosed in a 63 year old, male patient in 1993. After having experienced his second relapse upon standard therapy the patient was refractory to alemtuzumab treatment. Due to reduced performance status the patient was not eligible to standard chemotherapy and was enrolled into a phase II trial investigating PKC412. On conventional FLT3 mutation analysis the patient was considered to be FLT3 wild-type. Upon 8 and 29 days of treatment complete clearance of PB blast counts and BM blast infiltration was observed, respectively. Daily substitution of G-CSF resulted in transient recovery or the patients ANC′s. Since the patient showed an excellent clinical responsiveness, we reasoned whether the patient may have a yet unidentified FLT3 mutation. Sequence analysis revealed a novel point mutation in exon 21 of FLT3 (Y842C). Protein analysis of primary AML blasts showed constitutive FLT3 tyrosine-phosphorylation, ex vivo treatment with PKC412 caused significant inhibition of FLT3 and STAT5 activation. Further, in vivo analysis of FLT3 tyrosine-phosphorylation during the course of PKC412 treatment showed complete suppression of FLT3 activation within 8 days. Overexpression of FLT3-Y842C in 32D cells resulted in constitutive activation of FLT3 and STAT5 as well as in factor independent proliferation. Treatment with PKC412 caused inhibition of FLT3 tyrosine-phosphorylation, factor independent growth and apoptotic cell death. To further investigate the clinical significance of the novel Y842C mutation, the tyrosine kinase domain of FLT3 was investigated in 110 patients with AML using sequence analysis. Altogether, the novel mutation Y842C was identified in 2 patients, FLT-ITD in 22 patients and D835 in 7 patients, respectively. It is interesting to note that the recently described crystal structure of FLT3 reveals a critical role for Y842 in regulating the switch from the closed to the open (=active) conformation of the FLT3 activation loop. Since our data is consistent with the concept that the Y842C mutation results in constitutive activation of FLT3, it is tempting to speculate that the exchange of tyrosine for cysteine at position 842 disrupts the autoinhibited state of the FLT3 activation loop. Given that the novel mutation described here could only be identified by direct sequencing, it is likely that the number of mutations in this region of FLT3 is currently underestimated. Thus, extended sequence analysis of this mutational hotspot may be helpful in further defining the spectrum of TKI-sensitive FLT3 mutations in AML.

scholarly journals The MKK7 Gene Encodes a Group of c-Jun NH2-Terminal Kinase Kinases

1999 ◽  
Vol 19 (2) ◽  
pp. 1569-1581 ◽  
Author(s):  
Cathy Tournier ◽  
Alan J. Whitmarsh ◽  
Julie Cavanagh ◽  
Tamera Barrett ◽  
Roger J. Davis
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Cultured Cells ◽  
Biochemical Properties ◽  
Mitogen Activated Protein Kinase ◽  
Dual Specificity ◽  
Mitogen Activated Protein ◽  
Extracellular Stimuli ◽  
Jnk Activation

ABSTRACT The c-Jun NH2-terminal protein kinase (JNK) is a member of the mitogen-activated protein kinase (MAPK) group and is an essential component of a signaling cascade that is activated by exposure of cells to environmental stress. JNK activation is regulated by phosphorylation on both Thr and Tyr residues by a dual-specificity MAPK kinase (MAPKK). Two MAPKKs, MKK4 and MKK7, have been identified as JNK activators. Genetic studies demonstrate that MKK4 and MKK7 serve nonredundant functions as activators of JNK in vivo. We report here the molecular cloning of the gene that encodes MKK7 and demonstrate that six isoforms are created by alternative splicing to generate a group of protein kinases with three different NH2 termini (α, β, and γ isoforms) and two different COOH termini (1 and 2 isoforms). The MKK7α isoforms lack an NH2-terminal extension that is present in the other MKK7 isoforms. This NH2-terminal extension binds directly to the MKK7 substrate JNK. Comparison of the activities of the MKK7 isoforms demonstrates that the MKK7α isoforms exhibit lower activity, but a higher level of inducible fold activation, than the corresponding MKK7β and MKK7γ isoforms. Immunofluorescence analysis demonstrates that these MKK7 isoforms are detected in both cytoplasmic and nuclear compartments of cultured cells. The presence of MKK7 in the nucleus was not, however, required for JNK activation in vivo. These data establish that theMKK4 and MKK7 genes encode a group of protein kinases with different biochemical properties that mediate activation of JNK in response to extracellular stimuli.

scholarly journals p38β Mitogen-Activated Protein Kinase Modulates Its Own Basal Activity by Autophosphorylation of the Activating Residue Thr180 and the Inhibitory Residues Thr241 and Ser261

2016 ◽  
Vol 36 (10) ◽  
pp. 1540-1554 ◽  
Author(s):  
Jonah Beenstock ◽  
Dganit Melamed ◽  
Navit Mooshayef ◽  
Dafna Mordechay ◽  
Benjamin P. Garfinkel ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Protein Kinases ◽  
Mitogen Activated Protein Kinase ◽  
Activation Loop ◽  
Structural Element ◽  
Muscle Tissues ◽  
Mitogen Activated Protein ◽  
Loop Residue ◽  
Mapk Kinases

Many enzymes are self-regulated and can either inhibit or enhance their own catalytic activity. Enzymes that do both are extremely rare. Many protein kinases autoactivate by autophosphorylating specific sites at their activation loop and are inactivated by phosphatases. Although mitogen-activated protein kinases (MAPKs) are usually activated by dual phosphorylation catalyzed by MAPK kinases (MAPKKs), the MAPK p38β is exceptional and is capable of self-activation bycisautophosphorylation of its activation loop residue T180. We discovered that p38β also autophosphorylates intranstwo previously unknown sites residing within a MAPK-specific structural element known as the MAPK insert: T241 and S261. Whereas phosphorylation of T180 evokes catalytic activity, phosphorylation of S261 reduces the activity of T180-phosphorylated p38β, and phosphorylation of T241 reduces its autophosphorylation intrans. Both phosphorylations do not affect the activity of dually phosphorylated p38β. T241 of p38β is found phosphorylatedin vivoin bone and muscle tissues. In myogenic cell lines, phosphorylation of p38β residue T241 is correlated with differentiation to myotubes. T241 and S261 are also autophosphorylated in intrinsically active variants of p38α, but in this protein, they probably play a different role. We conclude that p38β is an unusual enzyme that automodulates its basal, MAPKK-independent activity by several autophosphorylation events, which enhance and suppress its catalytic activity.

scholarly journals Attenuation of yeast UPR is essential for survival and is mediated by IRE1 kinase

2011 ◽  
Vol 193 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Aditi Chawla ◽  
Sutapa Chakrabarti ◽  
Gourisankar Ghosh ◽  
Maho Niwa
Keyword(s):  
Er Stress ◽  
Kinase Domain ◽  
Activation Loop ◽  
Kinase Activation ◽  
Messenger Ribonucleic Acid ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response ◽  
In Cells

The unfolded protein response (UPR) activates Ire1, an endoplasmic reticulum (ER) resident transmembrane kinase and ribonuclease (RNase), in response to ER stress. We used an in vivo assay, in which disappearance of the UPR-induced spliced HAC1 messenger ribonucleic acid (mRNA) correlates with the recovery of the ER protein-folding capacity, to investigate the attenuation of the UPR in yeast. We find that, once activated, spliced HAC1 mRNA is sustained in cells expressing Ire1 carrying phosphomimetic mutations within the kinase activation loop, suggesting that dephosphorylation of Ire1 is an important step in RNase deactivation. Additionally, spliced HAC1 mRNA is also sustained after UPR induction in cells expressing Ire1 with mutations in the conserved DFG kinase motif (D828A) or a conserved residue (F842) within the activation loop. The importance of proper Ire1 RNase attenuation is demonstrated by the inability of cells expressing Ire1-D828A to grow under ER stress. We propose that the activity of the Ire1 kinase domain plays a role in attenuating its RNase activity when ER function is recovered.

scholarly journals The multifaceted allosteric regulation of Aurora kinase A

2018 ◽  
Vol 475 (12) ◽  
pp. 2025-2042 ◽  
Author(s):  
Nicholas Mark Levinson
Keyword(s):  
Molecular Level ◽  
Aurora Kinase ◽  
Kinase Domain ◽  
Regulatory Control ◽  
Activation Loop ◽  
Mitotic Spindles ◽  
Kinase Activation ◽  
Structure And Dynamics ◽  
Spindle Microtubules ◽  
Eukaryotic Organisms

The protein kinase Aurora A (AurA) is essential for the formation of bipolar mitotic spindles in all eukaryotic organisms. During spindle assembly, AurA is activated through two different pathways operating at centrosomes and on spindle microtubules. Recent studies have revealed that these pathways operate quite differently at the molecular level, activating AurA through multifaceted changes to the structure and dynamics of the kinase domain. These advances provide an intimate atomic-level view of the finely tuned regulatory control operating in protein kinases, revealing mechanisms of allosteric cooperativity that provide graded levels of regulatory control, and a previously unanticipated mechanism for kinase activation by phosphorylation on the activation loop. Here, I review these advances in our understanding of AurA function, and discuss their implications for the use of allosteric small molecule inhibitors to address recently discovered roles of AurA in neuroblastoma, prostate cancer and melanoma.

scholarly journals DYRK1A Autophosphorylation on Serine Residue 520 Modulates Its Kinase Activity via 14-3-3 Binding

2007 ◽  
Vol 18 (4) ◽  
pp. 1167-1178 ◽  
Author(s):  
Mónica Alvarez ◽  
Xavier Altafaj ◽  
Sergi Aranda ◽  
Susana de la Luna
Keyword(s):  
Protein Kinases ◽  
Kinase Activity ◽  
Dynamic Changes ◽  
Activated T Cells ◽  
Cellular Processes ◽  
Dual Specificity ◽  
Evolutionarily Conserved ◽  
The Family ◽  
Intramolecular Mechanism

Dual-specificity tyrosine-phosphorylated and regulated kinase (DYRK) proteins are an evolutionarily conserved family of protein kinases, with members identified from yeast to humans, that participate in a variety of cellular processes. DYRKs are serine/threonine protein kinases that are activated by autophosphorylation on a tyrosine residue in the activation loop. The family member DYRK1A has been shown to phosphorylate several cytosolic proteins and a number of splicing and transcription factors, including members of the nuclear factor of activated T cells family. In the present study, we show that DYRK1A autophosphorylates, via an intramolecular mechanism, on Ser-520, in the PEST domain of the protein. We also show that phosphorylation of this residue, which we show is subjected to dynamic changes in vivo, mediates the interaction of DYRK1A with 14-3-3β. A second 14-3-3 binding site is present within the N-terminal of the protein. In the context of the DYRK1A molecule, neither site can act independently of the other. Bacterially produced DYRK1A and the mutant DYRK1A/S520A have similar kinase activities, suggesting that Ser-520 phosphorylation does not affect the intrinsic kinase activity on its own. Instead, we demonstrate that this phosphorylation allows the binding of 14-3-3β, which in turn stimulates the catalytic activity of DYRK1A. These findings provide evidence for a novel mechanism for the regulation of DYRK1A kinase activity.

SU11248 is a novel FLT3 tyrosine kinase inhibitor with potent activity in vitro and in vivo

Blood ◽  
2003 ◽  
Vol 101 (9) ◽  
pp. 3597-3605 ◽  
Author(s):  
Anne-Marie O'Farrell ◽  
Tinya J. Abrams ◽  
Helene A. Yuen ◽  
Theresa J. Ngai ◽  
Sharianne G. Louie ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tyrosine Kinase ◽  
Xenograft Model ◽  
Kinase Domain ◽  
Tumor Xenograft ◽  
Activation Loop ◽  
Subcutaneous Tumor ◽  
Bone Marrow Engraftment

FLT3 (fms-related tyrosine kinase/Flk2/Stk-2) is a receptor tyrosine kinase (RTK) primarily expressed on hematopoietic cells. In blasts from acute myelogenous leukemia (AML) patients, 2 classes of FLT3 activating mutations have been identified: internal tandem duplication (ITD) mutations in the juxtamembrane domain (25%-30% of patients) and point mutations in the kinase domain activation loop (7%-8% of patients). FLT3-ITD mutations are the most common molecular defect identified in AML and have been shown to be an independent prognostic factor for decreased survival. FLT3-ITD is therefore an attractive molecular target for therapy. SU11248 is a recently described selective inhibitor with selectivity for split kinase domain RTKs, including platelet-derived growth factor receptors, vascular endothelial growth factor receptors, and KIT. We show that SU11248 also has potent activity against wild-type FLT3 (FLT3-WT), FLT3-ITD, and FLT3 activation loop (FLT3-Asp835) mutants in phosphorylation assays. SU11248 inhibits FLT3-driven phosphorylation and induces apoptosis in vitro. In addition, SU11248 inhibits FLT3-induced VEGF production. The in vivo efficacy of SU11248 was investigated in 2 FLT3-ITD models: a subcutaneous tumor xenograft model and a bone marrow engraftment model. We show that SU11248 (20 mg/kg/d) dramatically regresses FLT3-ITD tumors in the subcutaneous tumor xenograft model and prolongs survival in the bone marrow engraftment model. Pharmacokinetic and pharmacodynamic analysis in subcutaneous tumors showed that a single administration of an efficacious drug dose potently inhibits FLT3-ITD phosphorylation for up to 16 hours following a single dose. These results suggest that further exploration of SU11248 activity in AML patients is warranted.

scholarly journals dDYRK2 and Minibrain interact with the chromatin remodelling factors SNR1 and TRX

2006 ◽  
Vol 398 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Ross Kinstrie ◽  
Pamela A. Lochhead ◽  
Gary Sibbet ◽  
Nick Morrice ◽  
Vaughn Cleghon
Keyword(s):  
Chromatin Remodelling ◽  
Drosophila Embryo ◽  
Activation Loop ◽  
Tyrosine Residue ◽  
Yeast Two Hybrid ◽  
Binding Partners ◽  
C Terminus ◽  
Dual Specificity ◽  
Two Hybrid

The DYRKs (dual specificity tyrosine phosphorylation-regulated kinases) are a conserved family of protein kinases that autophosphorylate a tyrosine residue in their activation loop by an intra-molecular mechanism and phosphorylate exogenous substrates on serine/threonine residues. Little is known about the identity of true substrates for DYRK family members and their binding partners. To address this question, we used full-length dDYRK2 (Drosophila DYRK2) as bait in a yeast two-hybrid screen of a Drosophila embryo cDNA library. Of 14 independent dDYRK2 interacting clones identified, three were derived from the chromatin remodelling factor, SNR1 (Snf5-related 1), and three from the essential chromatin component, TRX (trithorax). The association of dDYRK2 with SNR1 and TRX was confirmed by co-immunoprecipitation studies. Deletion analysis showed that the C-terminus of dDYRK2 modulated the interaction with SNR1 and TRX. DYRK family member MNB (Minibrain) was also found to co-precipitate with SNR1 and TRX, associations that did not require the C-terminus of the molecule. dDYRK2 and MNB were also found to phosphorylate SNR1 at Thr102in vitro and in vivo. This phosphorylation required the highly conserved DH-box (DYRK homology box) of dDYRK2, whereas the DH-box was not essential for phosphorylation by MNB. This is the first instance of phosphorylation of SNR1 or any of its homologues and implicates the DYRK family of kinases with a role in chromatin remodelling.

Sign in / Sign up

Export Citation Format

Share Document