scholarly journals Flt-1 lacking the tyrosine kinase domain is sufficient for normal development and angiogenesis in mice

1998 ◽  
Vol 95 (16) ◽  
pp. 9349-9354 ◽  
Author(s):  
Sachie Hiratsuka ◽  
Osamu Minowa ◽  
Junko Kuno ◽  
Tetsuo Noda ◽  
Masabumi Shibuya
Keyword(s):  
Embryonic Development ◽  
Tyrosine Kinase ◽  
Ligand Binding ◽  
Tyrosine Kinases ◽  
Kinase Domain ◽  
Biological Role ◽  
Tyrosine Kinase Domain ◽  
Vascular Endothelial ◽  
Null Mutant Mice ◽  
Endothelial Growth Factor

Receptor tyrosine kinases Flt-1 and Flk-1/KDR, and their ligand, the vascular endothelial growth factor (VEGF), were shown to be essential for angiogenesis in the mouse embryo by gene targeting. Flk-1/KDR null mutant mice exhibited impaired endothelial and hematopoietic cell development. On the other hand, Flt-1 null mutation resulted in early embryonic death at embryonic day 8.5, showing disorganization of blood vessels, such as overgrowth of endothelial cells. Flt-1 differs from Flk-1 in that it displays a higher affinity for VEGF but lower kinase activity, suggesting the importance of its extracellular domain. To examine the biological role of Flt-1 in embryonic development and vascular formation, we deleted the kinase domain without affecting the ligand binding region. Flt-1 tyrosine kinase-deficient homozygous mice (flt-1TK−/−) developed normal vessels and survived. However, VEGF-induced macrophage migration was strongly suppressed inflt-1TK−/−mice. These results indicate that Flt-1 without tyrosine kinase domain is sufficient to allow embryonic development with normal angiogenesis, and that a receptor tyrosine kinase plays a main biological role as a ligand-binding molecule.

Functional dissection of p56lck, a protein tyrosine kinase which mediates interleukin-2-induced activation of the c-fos gene

1994 ◽  
Vol 14 (9) ◽  
pp. 5812-5819
Author(s):  
H Shibuya ◽  
K Kohu ◽  
K Yamada ◽  
E L Barsoumian ◽  
R M Perlmutter ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Gene Activation ◽  
Interleukin 2 ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Amino Acid Residues ◽  
Protein Tyrosine ◽  
Responsive Element

Members of the newly identified receptor family for cytokines characteristically lack the intrinsic protein tyrosine kinase domain that is a hallmark of other growth factor receptors. Instead, accumulating evidence suggests that these receptors utilize nonreceptor-type protein tyrosine kinases for downstream signal transduction by cytokines. We have shown previously that the interleukin-2 receptor beta-chain interacts both physically and functionally with a Src family member, p56lck, and that p56lck activation leads to induction of the c-fos gene. However, the mechanism linking p56lck activation with c-fos induction remains unelucidated. In the present study, we systematically examined the extent of c-fos promoter activation by expression of a series of p56lck mutants, using a transient cotransfection assay. The results define a set of the essential amino acid residues that regulate p56lck induction of the c-fos promoter. We also provide evidence that the serum-responsive element and sis-inducible element are both targets through which p56lck controls c-fos gene activation.

scholarly journals FLT4 Mutations Are Associated with Segmental Lymphatic Dysfunction and Initial Lymphatic Aplasia in Patients with Milroy Disease

Genes ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1611
Author(s):  
Ningfei Liu ◽  
Minzhe Gao
Keyword(s):  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Clinical Signs ◽  
Lymphatic Vessels ◽  
Growth Factor Receptor ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Missense Mutations ◽  
History Of ◽  
Endothelial Growth Factor

This study explored mutations in the Fms-related tyrosine kinase 4/vascular endothelial growth factor receptor 3 gene (FLT4) and lymphatic defects in patients with Milroy disease (MD). Twenty-nine patients with lower limb lymphedema were enrolled. Sixteen patients had a familial history of MD, while 13 patients exhibited sporadic MD. Clinical signs, FLT4 mutations, indocyanine green (ICG) lymphography findings, and skin tissue immunohistochemical staining results were evaluated. Twenty-eight variants in FLT4 were identified. Twelve of these have previously been reported, while 16 are novel. Of the 28 variants, 26 are missense mutations, and the remaining two comprise a splicing mutation and a non-frame shift mutation. Twenty-five variants are located in the intracellular protein tyrosine kinase domain; three are located in the extracellular immunoglobulin domain. Substantially delayed contrast-enhanced tortuous lymphatic vessels were visualized to the ankle or knee level in 15 of 23 patients who underwent ICG lymphography. No initial lymphatic vessels were visualized in skin specimens from four patients who did not exhibit lymphatic vessels during imaging analyses. No specific variant was identified in relation to the unique clinical phenotype. Segmental dysfunction of lymphatic vessels and initial lymphatic aplasia are present in MD patients with FLT4 mutations.

scholarly journals Comparison of tyrosine kinase domain properties for the neurotrophin receptors TrkA and TrkB

2020 ◽  
Vol 477 (20) ◽  
pp. 4053-4070
Author(s):  
Stephen C. Artim ◽  
Anatoly Kiyatkin ◽  
Mark A. Lemmon
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Catalytic Efficiency ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Signaling Dynamics ◽  
Cellular Context ◽  
And Function ◽  
High Degree

The tropomyosin-related kinase (Trk) family consists of three receptor tyrosine kinases (RTKs) called TrkA, TrkB, and TrkC. These RTKs are regulated by the neurotrophins, a class of secreted growth factors responsible for the development and function of neurons. The Trks share a high degree of homology and utilize overlapping signaling pathways, yet their signaling is associated with starkly different outcomes in certain cancers. For example, in neuroblastoma, TrkA expression and signaling correlates with a favorable prognosis, whereas TrkB is associated with poor prognoses. To begin to understand how activation of the different Trks can lead to such distinct cellular outcomes, we investigated differences in kinase activity and duration of autophosphorylation for the TrkA and TrkB tyrosine kinase domains (TKDs). We find that the TrkA TKD has a catalytic efficiency that is ∼2-fold higher than that of TrkB, and becomes autophosphorylated in vitro more rapidly than the TrkB TKD. Studies with mutated TKD variants suggest that a crystallographic dimer seen in many TrkA (but not TrkB) TKD crystal structures, which involves the kinase-insert domain, may contribute to this enhanced TrkA autophosphorylation. Consistent with previous studies showing that cellular context determines whether TrkB signaling is sustained (promoting differentiation) or transient (promoting proliferation), we also find that TrkB signaling can be made more transient in PC12 cells by suppressing levels of p75NTR. Our findings shed new light on potential differences between TrkA and TrkB signaling, and suggest that subtle differences in signaling dynamics can lead to substantial shifts in the cellular outcome.

A novel uniquely ovary-expressed insulin-like receptor in the female prawn, Macrobrachium rosenbergii (Decapoda, Palaemonidae)

Crustaceana ◽  
2021 ◽  
Vol 94 (3) ◽  
pp. 263-281
Author(s):  
Hai-Jing Xu ◽  
Jian-Wen Li ◽  
Yi-Lai Chen ◽  
Jin-Shu Yang ◽  
Wen-Ming Ma ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Ligand Binding ◽  
Transmembrane Domain ◽  
Macrobrachium Rosenbergii ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Distribution Analysis ◽  
Female Reproduction ◽  
Separate Branch ◽  
Insulin Signalling Pathway

Abstract The insulin signalling pathway is one of the most studied pathways, including ovary maturation and female reproduction. However, downstream elements involved in this cascade remain unknown. Here, we identified and characterized an insulin-like receptor (IR) in female Macrobrachium rosenbergii, and named as Mro-IR. The deduced Mro-IR contained conserved domains of IR proteins, including two ligand-binding domains, a furin-like domain, two fibronectin-3 domains, a transmembrane domain and an intracellular tyrosine kinase domain in order. Multiple sequence alignment of the first ligand-binding domain and the tyrosine kinase domain in Mro-IR revealed a high degree of similarity to other representative IRs. Mro-IR was clustered into a separate branch with IRs from decapods by phylogenetic analysis. Additionally, tissue distribution analysis showed that Mro-IR was uniquely expressed in the ovary of M. rosenbergii. This study would possibly provide a new highlight to the molecular mechanism of insulin-like signalling cascade, regulating female sexual differentiation in crustaceans.

scholarly journals Efficient CD28 signalling leads to increases in the kinase activities of the TEC family tyrosine kinase EMT/ITK/TSK and the SRC family tyrosine kinase LCK

1998 ◽  
Vol 330 (3) ◽  
pp. 1123-1128 ◽  
Author(s):  
Spencer GIBSON ◽  
Ken TRUITT ◽  
Yiling LU ◽  
Ruth LAPUSHIN ◽  
Humera KHAN ◽  
...  
Keyword(s):  
T Cell ◽  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
T Cell Activation ◽  
Tyrosine Kinases ◽  
Cell Activation ◽  
Interleukin 2 ◽  
Cell Receptor ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain

Optimal T cell activation requires crosslinking of the T cell receptor (TCR) concurrently with an accessory receptor, most efficiently CD28. Crosslinking of CD28 leads to increased interleukin 2 (IL2) production, inhibition of anergy and prevention of programmed cell death. Crosslinking of CD28 leads to rapid increases in tyrosine phosphorylation of specific intracellular substrates including CD28 itself. Since CD28 does not encode an intrinsic tyrosine kinase domain, CD28 must activate an intracellular tyrosine kinase(s). Indeed, crosslinking of CD28 increases the activity of the intracellular tyrosine kinases EMT/ITK and LCK. The phosphatidylinositol 3-kinase (PI3K) and GRB2 binding site in CD28 is dispensable for optimal IL2 production in Jurkat T cells. We demonstrate herein that murine Y170 (equivalent to human Y173) in CD28 is also dispensable for activation of the SRC family tyrosine kinase LCK and the TEC family tyrosine kinase EMT/ITK. In contrast, the distal three tyrosines in CD28 are required for optimal IL2 production as well as for optimal activation of the LCK and EMT/ITK tyrosine kinases. The distal three tyrosines of CD28, however, are not required for recruitment of PI3K to CD28. Furthermore, PI3K is recruited to CD28 in JCaM1 cells which lack LCK and in which EMT/ITK is not activated by ligation of CD28. Thus optimal activation of LCK or EMT/ITK is not obligatory for recruitment of PI3K to CD28 and thus is also not required for tyrosine phosphorylation of the YMNM motif in CD28. Taken together the data indicate that the distal three tyrosines in CD28 are integral to the activation of LCK and EMT/ITK and for subsequent IL2 production.

Phosphorylation of Receptor Tyrosine Kinase ROR1 At Tyrosine 641, 646 and Serine 652 residues Might Be of Importance for the Survival of CLL Leukemic Cells

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3885-3885
Author(s):  
Mohammad Hojjat-Farsangi ◽  
Amir Hossein Daneshmanesh ◽  
Martin Norin ◽  
Åsa Sandin ◽  
Abdul Salam Khan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Tyrosine Kinase ◽  
Western Blot ◽  
Tyrosine Kinases ◽  
Conflicts Of Interest ◽  
Annexin V ◽  
Kinase Domain ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Tyrosine Kinase Domain

Abstract Abstract 3885 Background: Receptor tyrosine kinases (RTK) play crucial roles for different normal cellular processes as cell proliferation/differentiation, apoptosis and survival, as well as for the malignant phenotype of many types of cancer. ROR1, as a member of twenty RTKs families, has important functions during normal embryogenesis. ROR1 has shown to be overexpressed in chronic lymphocytic leukemia (CLL), mantle cell lymphoma and other hematological malignancies, as well as in solid tumors. ROR1 inhibition in CLL cells and cell lines with high expression of ROR1 induced specific apoptosis of the cells. In this study, we investigated the effects of an anti-ROR1 mAb against the extracellular CRD domain for specific dephosphorylation at the tyrosine kinase domain of ROR1 in CLL cells. The CRD domain contains a frizzle receptor, which is considered to be the ligand-binding region for e.g. Wnt5a. Wnt5a has been suggested to stimulate growth of CLL cells. Aims: To investigate phosphorylation of tyrosine and serine residues, within the tyrosine kinase domain of ROR1, of importance for survival of CLL cells. Methods: Bioinformatic analysis of the ROR1 structure revealed that three amino acid residues in the tyrosine kinase domain might be critically phosphorylated. Based on this prediction, a 19 amino acid long peptide, phosphorylated at two tyrosine (tyrosine 641, 646) and one serine (serine 652) residues was designed and used for immunization of rabbits. An anti-phospho-ROR1 (pROR1) polyclonal antibody (pAb) with high titers of anti-pROR1 pAb was purified, using phospho-peptide affinity chromatography. The specificity of anti-pROR1 pAb was determined by ELISA, immunoprecipitation (IP) and western blot experiments. An anti-ROR1 mAb (IgG) (CRD 1D8 clone) was used to analyse the effects on ROR1 phosphorylation in CLL cells at tyrosine 641, 646 and serine 652 residues preceding apoptosis. ROR1 phosphorylation was investigated by western blot and IP of ROR1 probed with anti-pROR1 pAb, from untreated and CLL cells treated with the anti-CRD 1D8 mAb. Quantitative intracellular staining of ROR1 by flowcytometry in time kinetics experiment after treatment with anti-CRD 1D8 mAb was also used to check phosphorylation of ROR1. Annexin V/PI staining (flowcytometry), MTT assay, PARP and caspase 8 cleavage as well as MCL-1 protein (western blot) were used for detection of apoptosis. To investigate phosphorylation and localization of 64–130 kDa ROR1 isoforms in various compartments of CLL cells, lysates were prepared from the nucleus and cytoplasmic proteins of CLL cells. Results: Two tyrosine (641, 646) residues and one serine (652) residue of the tyrosine kinase domain were phosphorylated in CLL cells. As previously described (Mellstedt et al, Abstract No: 1771, 53th ASH annals meeting, 2011), the 64, 105 and 130 kDa ROR1 isoforms were shown to be constitutively phosphorylated at tyrosine and serine residues in CLL leukemic cells. Treatment of CLL cells with an anti-ROR1 mAb against the CRD domain induced rapid dephosphorylation of ROR1 at tyrosine 641, 646 and serine 652 residues within 20 min and gradually increased up to 4 hours. The phosphorylated 64 kDa ROR1 isoform was localized to the nucleus of CLL cells and probably represents an intracellular part of ROR1, while the ROR1 130 kDa isoform was presented both in cytoplasm and nucleus of CLL cells. Conclusion: Our data show that the ROR1 molecule is phosphorylated at tyrosine 641, 646 and serine 652 residues. The presence of 64 and 130 kDa ROR1 isoforms in the nucleus of CLL cells may suggest a role of these isoforms as transcription factors. Collectively, the data might suggest that phosphorylated ROR1 may be an important protein for the growth of CLL cells as well as an interesting structure to target in a therapeutic intervention. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Regulation of the Jak2 Tyrosine Kinase by Its Pseudokinase Domain

2000 ◽  
Vol 20 (10) ◽  
pp. 3387-3395 ◽  
Author(s):  
Pipsa Saharinen ◽  
Kati Takaluoma ◽  
Olli Silvennoinen
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Phosphatases ◽  
Kinase Domain ◽  
Sh2 Domain ◽  
Tyrosine Kinase Domain ◽  
Functional Roles ◽  
Domain Of Unknown Function ◽  
Ligand Stimulation ◽  
Induced Aggregation

ABSTRACT Activation of Jak tyrosine kinases through hematopoietic cytokine receptors occurs as a consequence of ligand-induced aggregation of receptor-associated Jaks and their subsequent autophosphorylation. Jak kinases consist of a C-terminal tyrosine kinase domain, a pseudokinase domain of unknown function, and Jak homology (JH) domains 3 to 7, implicated in receptor-Jak interaction. We analyzed the functional roles of the different protein domains in activation of Jak2. Deletion analysis of Jak2 showed that the pseudokinase domain but not JH domains 3 to 7 negatively regulated the catalytic activity of Jak2 as well as Jak2-mediated activation of Stat5. Phosphorylation of Stat5 by wild-type Jak2 was dependent on the SH2 domain of Stat5; however, this requirement was lost upon deletion of the pseudokinase domain of Jak2. Investigation of the mechanisms of the pseudokinase domain-mediated inhibition of Jak2 suggested that this regulation did not involve protein tyrosine phosphatases. Instead, analysis of interactions between the tyrosine kinase domain and Jak2 suggested that the pseudokinase domain interacted with the kinase domain. Furthermore, coexpression of the pseudokinase domain inhibited the activity of the single tyrosine kinase domain. Finally, deletion of the pseudokinase domain of Jak2 deregulated signal transduction through the gamma interferon receptor by significantly increasing ligand-independent activation of Stat transcription factors. These results indicate that the pseudokinase domain negatively regulates the activity of Jak2, probably through an interaction with the kinase domain, and this regulation is required to keep Jak2 inactive in the absence of ligand stimulation. Furthermore, the pseudokinase domain may have a role in regulation of Jak2-substrate interactions.

scholarly journals Functional dissection of p56lck, a protein tyrosine kinase which mediates interleukin-2-induced activation of the c-fos gene.

1994 ◽  
Vol 14 (9) ◽  
pp. 5812-5819 ◽  
Author(s):  
H Shibuya ◽  
K Kohu ◽  
K Yamada ◽  
E L Barsoumian ◽  
R M Perlmutter ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Gene Activation ◽  
Interleukin 2 ◽  
Kinase Domain ◽  
Tyrosine Kinase Domain ◽  
Amino Acid Residues ◽  
Protein Tyrosine ◽  
Responsive Element

Members of the newly identified receptor family for cytokines characteristically lack the intrinsic protein tyrosine kinase domain that is a hallmark of other growth factor receptors. Instead, accumulating evidence suggests that these receptors utilize nonreceptor-type protein tyrosine kinases for downstream signal transduction by cytokines. We have shown previously that the interleukin-2 receptor beta-chain interacts both physically and functionally with a Src family member, p56lck, and that p56lck activation leads to induction of the c-fos gene. However, the mechanism linking p56lck activation with c-fos induction remains unelucidated. In the present study, we systematically examined the extent of c-fos promoter activation by expression of a series of p56lck mutants, using a transient cotransfection assay. The results define a set of the essential amino acid residues that regulate p56lck induction of the c-fos promoter. We also provide evidence that the serum-responsive element and sis-inducible element are both targets through which p56lck controls c-fos gene activation.

scholarly journals Neuropilins in the Context of Tumor Vasculature

2019 ◽  
Vol 20 (3) ◽  
pp. 639 ◽  
Author(s):  
Stephan Niland ◽  
Johannes A. Eble
Keyword(s):  
Endothelial Cells ◽  
Tyrosine Kinases ◽  
Tumor Therapy ◽  
Tumor Vasculature ◽  
Kinase Domain ◽  
Vascular Endothelial ◽  
Protein Kinase Domain ◽  
Neuropilin 1 ◽  
Membrane Spanning ◽  
Endothelial Growth Factor

Neuropilin-1 and Neuropilin-2 form a small family of plasma membrane spanning receptors originally identified by the binding of semaphorin and vascular endothelial growth factor. Having no cytosolic protein kinase domain, they function predominantly as co-receptors of other receptors for various ligands. As such, they critically modulate the signaling of various receptor tyrosine kinases, integrins, and other molecules involved in the regulation of physiological and pathological angiogenic processes. This review highlights the diverse neuropilin ligands and interacting partners on endothelial cells, which are relevant in the context of the tumor vasculature and the tumor microenvironment. In addition to tumor cells, the latter contains cancer-associated fibroblasts, immune cells, and endothelial cells. Based on the prevalent neuropilin-mediated interactions, the suitability of various neuropilin-targeted substances for influencing tumor angiogenesis as a possible building block of a tumor therapy is discussed.

scholarly journals Membrane Fixation of Vascular Endothelial Growth Factor Receptor 1 Ligand-Binding Domain Is Important for Vasculogenesis and Angiogenesis in Mice

2005 ◽  
Vol 25 (1) ◽  
pp. 346-354 ◽  
Author(s):  
Sachie Hiratsuka ◽  
Kazuki Nakao ◽  
Kenji Nakamura ◽  
Motoya Katsuki ◽  
Yoshiro Maru ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Endothelial Cells ◽  
Growth Factor ◽  
Tyrosine Kinase ◽  
Ligand Binding ◽  
Early Embryogenesis ◽  
Vascular Endothelial ◽  
Vasculogenesis And Angiogenesis ◽  
Endothelial Growth Factor ◽  
Deficient Mice

ABSTRACT Vascular endothelial growth factor (VEGF) regulates vasculogenesis and angiogenesis by using two tyrosine kinase receptors, VEGFR1 and VEGFR2. VEGFR1 null mutant mice die on embryonic day 8.5 (E8.5) to E9.0 due to an overgrowth of endothelial cells and vascular disorganization, suggesting that VEGFR1 plays a negative role in angiogenesis. We previously showed that the tyrosine kinase (TK) domain of VEGFR1 is dispensable for embryogenesis, since VEGFR1 TK-deficient mice survived and were basically healthy. However, the molecular basis for this is not yet clearly understood. To test the hypothesis that the specific role of VEGFR1 during early embryogenesis is to recruit its ligand to the cell membrane, we deleted the transmembrane (TM) domain in TK-deficient VEGFR1 mice. Surprisingly, about half of the VEGFR1(TM-TK)-deficient mice succumbed to embryonic lethality due to a poor development of blood vessels, whereas other mice were healthy. In VEGFR1(TM-TK)−/− mice with growth arrest, membrane-targeted VEGF was reduced, resulting in the suppression of VEGFR2 phosphorylation. Furthermore, the embryonic lethality in VEGFR1(TM-TK)−/− mice was significantly increased to 80 to 90% when the genotype of VEGFR2 was changed from homozygous (+/+) to heterozygous (+/−) in 129/C57BL6 mice. These results strongly suggest that the membrane-fixed ligand-binding region of VEGFR1 traps VEGF for the appropriate regulation of VEGF signaling in vascular endothelial cells during early embryogenesis.

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