Unlocking Doors without Keys: Activation of Src by Truncated C-terminal Intracellular Receptor Tyrosine Kinases Lacking Tyrosine Kinase Activity

A miniature tyrosinase-based electrochemical sensing platform for label-free detection of protein tyrosine kinase activity was developed in this study. The developed miniature sensing platform can detect the substrate peptides for tyrosine kinases, such as c-Src, Hck and Her2, in a low sample volume (1–2 μL). The developed sensing platform exhibited a high reproducibility for repetitive measurement with an RSD (relative standard deviation) of 6.6%. The developed sensing platform can detect the Hck and Her2 in a linear range of 1–200 U/mL with the detection limit of 1 U/mL. The sensing platform was also effective in assessing the specificity and efficacies of the inhibitors for protein tyrosine kinases. This is demonstrated by the detection of significant inhibition of Hck (~88.1%, but not Her2) by the Src inhibitor 1, an inhibitor for Src family kinases, as well as the significant inhibition of Her2 (~91%, but not Hck) by CP-724714 through the platform. These results suggest the potential of the developed miniature sensing platform as an effective tool for detecting different protein tyrosine kinase activity and for accessing the inhibitory effect of various inhibitors to these kinases.

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Topology of Streptococcus pneumoniae CpsC, a Polysaccharide Copolymerase and Bacterial Protein Tyrosine Kinase Adaptor Protein

Journal of Bacteriology ◽

10.1128/jb.02106-14 ◽

2014 ◽

Vol 197 (1) ◽

pp. 120-127 ◽

Cited By ~ 4

Author(s):

Jonathan J. Whittall ◽

Renato Morona ◽

Alistair J. Standish

Keyword(s):

Streptococcus Pneumoniae ◽

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Kinase Activity ◽

Tyrosine Phosphatase ◽

Adaptor Protein ◽

Tyrosine Kinase Activity ◽

Content Type ◽

Protein Tyrosine ◽

C Terminus

In Gram-positive bacteria, tyrosine kinases are split into two proteins, the cytoplasmic tyrosine kinase and a transmembrane adaptor protein. InStreptococcus pneumoniae, this transmembrane adaptor is CpsC, with the C terminus of CpsC critical for interaction and subsequent tyrosine kinase activity of CpsD. Topology predictions suggest that CpsC has two transmembrane domains, with the N and C termini present in the cytoplasm. In order to investigate CpsC topology, we used a chromosomal hemagglutinin (HA)-tagged Cps2C protein inS. pneumoniaestrain D39. Incubation of both protoplasts and membranes with carboxypeptidase B (CP-B) resulted in complete degradation of HA-Cps2C in all cases, indicating that the C terminus of Cps2C was likely extracytoplasmic and hence that the protein's topology was not as predicted. Similar results were seen with membranes fromS. pneumoniaestrain TIGR4, indicating that Cps4C also showed similar topology. A chromosomally encoded fusion of HA-Cps2C and Cps2D was not degraded by CP-B, suggesting that the fusion fixed the C terminus within the cytoplasm. However, capsule synthesis was unaltered by this fusion. Detection of the CpsC C terminus by flow cytometry indicated that it was extracytoplasmic in approximately 30% of cells. Interestingly, a mutant in the protein tyrosine phosphatase CpsB had a significantly greater proportion of positive cells, although this effect was independent of its phosphatase activity. Our data indicate that CpsC possesses a varied topology, with the C terminus flipping across the cytoplasmic membrane, where it interacts with CpsD in order to regulate tyrosine kinase activity.

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Gene regulation by tyrosine kinases: src protein activates various promoters, including c-fos

Molecular and Cellular Biology ◽

10.1128/mcb.9.6.2493-2499.1989 ◽

1989 ◽

Vol 9 (6) ◽

pp. 2493-2499

Author(s):

M Fujii ◽

D Shalloway ◽

I M Verma

Keyword(s):

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Kinase Activity ◽

Cellular Transformation ◽

Membrane Association ◽

Protein Tyrosine Phosphorylation ◽

Promoter Activation ◽

Tyrosine Kinase Activity ◽

Atp Binding Site ◽

Src Gene

A promoter of the nuclear proto-oncogene fos was activated by cotransfection with the viral src gene. Ability to transactivate the c-fos promoter was dependent on tyrosine kinase activity, because (i) src mutants which have reduced tyrosine kinase activity due to mutation of Tyr-416 to Phe showed lower promoter activation, (ii) pp60c-src mutants which have increased tyrosine kinase activity due to mutation of Tyr-527 to Phe also augmented c-fos promoter induction, and (iii) mutation in the ATP-binding site of pp60v-src strongly suppressed c-fos promoter activation. Tyrosine kinase activity alone, however, was not sufficient for promoter activation, because of pp60v-src mutant which lacked its myristylation site and consequently membrane association showed no increased c-fos promoter activation. Both the tyrosine kinase- and membrane-association-defective mutants were also unable to induce transformation. Therefore, phosphorylation of membrane-associated substrates appears to be required for both gene expression and cellular transformation by the src protein. Two regions of the c-fos promoter located between positions -362 and -324 and positions -323 and -294 were responsive to src stimulation. We believe that protein tyrosine phosphorylation represents an important step of signal transduction from the membrane to the nucleus.

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Novel yeast protein kinase (YPK1 gene product) is a 40-kilodalton phosphotyrosyl protein associated with protein-tyrosine kinase activity.

Molecular and Cellular Biology ◽

10.1128/mcb.10.12.6244 ◽

1990 ◽

Vol 10 (12) ◽

pp. 6244-6256 ◽

Cited By ~ 51

Author(s):

D Dailey ◽

G L Schieven ◽

M Y Lim ◽

H Marquardt ◽

T Gilmore ◽

...

Keyword(s):

Protein Kinase ◽

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Protein Tyrosine Kinase ◽

Kinase Activity ◽

Protein Tyrosine Kinases ◽

Tyrosine Kinase Activity ◽

Protein Tyrosine ◽

Protein Tyrosine Kinase Activity

Extracts of bakers' yeast (Saccharomyces cerevisiae) contain protein-tyrosine kinase activity that can be detected with a synthetic Glu-Tyr copolymer as substrate (G. Schieven, J. Thorner, and G.S. Martin, Science 231:390-393, 1986). By using this assay in conjunction with ion-exchange and affinity chromatography, a soluble tyrosine kinase activity was purified over 8,000-fold from yeast extracts. The purified activity did not utilize typical substrates for mammalian protein-tyrosine kinases (enolase, casein, and histones). The level of tyrosine kinase activity at all steps of each preparation correlated with the content of a 40-kDa protein (p40). Upon incubation of the most highly purified fractions with Mn-ATP or Mg-ATP, p40 was the only protein phosphorylated on tyrosine. Immunoblotting of purified p40 or total yeast extracts with antiphosphotyrosine antibodies and phosphoamino acid analysis of 32P-labeled yeast proteins fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the 40-kDa protein is normally phosphorylated at tyrosine in vivo. 32P-labeled p40 immunoprecipitated from extracts of metabolically labeled cells by affinity-purified anti-p40 antibodies contained both phosphoserine and phosphotyrosine. The gene encoding p40 (YPK1) was cloned from a yeast genomic library by using oligonucleotide probes designed on the basis of the sequence of purified peptides. As deduced from the nucleotide sequence of YPK1, p40 is homologous to known protein kinases, with features that resemble known protein-serine kinases more than known protein-tyrosine kinases. Thus, p40 is a protein kinase which is phosphorylated in vivo and in vitro at both tyrosine and serine residues; it may be a novel type of autophosphorylating tyrosine kinase, a bifunctional (serine/tyrosine-specific) protein kinase, or a serine kinase that is a substrate for an associated tyrosine kinase.

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The Paradigm of Targeting an Oncogenic Tyrosine Kinase: Lesson from BCR-ABL

10.5772/intechopen.97528 ◽

2021 ◽

Author(s):

Enrico Bracco ◽

M. Shahzad Ali ◽

Stefano Magnati ◽

Giuseppe Saglio

Keyword(s):

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Molecular Mechanisms ◽

Kinase Activity ◽

Fusion Gene ◽

Lymphoblastic Leukemia ◽

Philadelphia Chromosome ◽

Protein Tyrosine Phosphatases ◽

Selective Inhibition ◽

Tyrosine Kinase Activity

The aberrant tyrosine phosphorylation, either due to constitutive tyrosine kinases (TKs) or to inactivation of protein tyrosine phosphatases (PTPs), is a widespread feature of many cancerous cells. The BCR-ABL fusion protein, which arises from the Philadelphia chromosome, is a molecular distinct and peculiar trait of some kind of leukemia, namely Chronic Myeloid and Acute Lymphoblastic Leukemia, and displays constitutive tyrosine kinase activity. In the chapter, we will highlight the milestones that had led to the identification of the BCR-ABL fusion gene and its role as the only molecular pathogenic event sufficient to elicit and sustain chronic myeloid leukemia. We will also discuss the effort made to unveil the molecular mechanisms of action of the chimeric tyrosine kinase that eventually lead to aberrant cell proliferation and impaired cell-death. Furthermore, we will also review the lesson learned from the selective inhibition of BCR-ABL which currently represent a breakthrough in the treatment of several tumors characterized by defective tyrosine kinase activity.

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Novel yeast protein kinase (YPK1 gene product) is a 40-kilodalton phosphotyrosyl protein associated with protein-tyrosine kinase activity

Molecular and Cellular Biology ◽

10.1128/mcb.10.12.6244-6256.1990 ◽

1990 ◽

Vol 10 (12) ◽

pp. 6244-6256

Author(s):

D Dailey ◽

G L Schieven ◽

M Y Lim ◽

H Marquardt ◽

T Gilmore ◽

...

Keyword(s):

Protein Kinase ◽

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Protein Tyrosine Kinase ◽

Kinase Activity ◽

Protein Tyrosine Kinases ◽

Tyrosine Kinase Activity ◽

Protein Tyrosine ◽

Protein Tyrosine Kinase Activity

Extracts of bakers' yeast (Saccharomyces cerevisiae) contain protein-tyrosine kinase activity that can be detected with a synthetic Glu-Tyr copolymer as substrate (G. Schieven, J. Thorner, and G.S. Martin, Science 231:390-393, 1986). By using this assay in conjunction with ion-exchange and affinity chromatography, a soluble tyrosine kinase activity was purified over 8,000-fold from yeast extracts. The purified activity did not utilize typical substrates for mammalian protein-tyrosine kinases (enolase, casein, and histones). The level of tyrosine kinase activity at all steps of each preparation correlated with the content of a 40-kDa protein (p40). Upon incubation of the most highly purified fractions with Mn-ATP or Mg-ATP, p40 was the only protein phosphorylated on tyrosine. Immunoblotting of purified p40 or total yeast extracts with antiphosphotyrosine antibodies and phosphoamino acid analysis of 32P-labeled yeast proteins fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the 40-kDa protein is normally phosphorylated at tyrosine in vivo. 32P-labeled p40 immunoprecipitated from extracts of metabolically labeled cells by affinity-purified anti-p40 antibodies contained both phosphoserine and phosphotyrosine. The gene encoding p40 (YPK1) was cloned from a yeast genomic library by using oligonucleotide probes designed on the basis of the sequence of purified peptides. As deduced from the nucleotide sequence of YPK1, p40 is homologous to known protein kinases, with features that resemble known protein-serine kinases more than known protein-tyrosine kinases. Thus, p40 is a protein kinase which is phosphorylated in vivo and in vitro at both tyrosine and serine residues; it may be a novel type of autophosphorylating tyrosine kinase, a bifunctional (serine/tyrosine-specific) protein kinase, or a serine kinase that is a substrate for an associated tyrosine kinase.

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Dephosphorylation or antibody binding to the carboxy terminus stimulates pp60c-src

Molecular and Cellular Biology ◽

10.1128/mcb.6.12.4467-4477.1986 ◽

1986 ◽

Vol 6 (12) ◽

pp. 4467-4477

Author(s):

J A Cooper ◽

C S King

Keyword(s):

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Protein Tyrosine Kinase ◽

Kinase Activity ◽

Antibody Binding ◽

Carboxy Terminus ◽

Tyrosine Kinase Activity ◽

Protein Tyrosine ◽

Protein Tyrosine Kinase Activity

Phosphorylation of pp60c-src at Tyr-527, six residues from the carboxy terminus, has been implicated in regulation of the protein-tyrosine kinase activity of pp60c-src. Here we show that dephosphorylation of pp60c-src by phosphatase treatment in vitro caused a 10- to 20-fold increase in pp60c-src protein-tyrosine kinase activity. Binding of specific antibody to the region of pp60c-src which contains phosphotyrosine-527 also increased kinase activity. Each treatment increased phosphorylation of added substrates and of Tyr-416 within pp60c-src by a similar mechanism that involved altered interactions with ATP and increased catalytic rate. We suggest that the phosphorylated carboxy terminus acts as an inhibitor of the protein kinase domain of pp60c-src, unless its conformation is altered by either dephosphorylation or antibody binding. The antibody additionally stimulated the phosphorylation of forms of pp60c-src that had reduced gel mobility, much like those phosphorylated in kinase reactions containing pp60c-src activated by polyomavirus medium tumor antigen. These in vitro experiments provide models for the activation of pp60c-src in cells transformed by polyomavirus. We also show that autophosphorylation of pp60c-src at Tyr-527 occurs only to a very limited extent in vitro, even when Tyr-527 is made available for phosphorylation by treatment with phosphatase. This suggests that other protein-tyrosine kinases may normally phosphorylate Tyr-527 and regulate pp60c-src in the cell.

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Tyrosine Kinase Proteins profiling of Nilotinib Resistant Chronic Myelogenous Leukemia Cells Unravels a Tyrosine Kinase-Mediated Bypass.

Blood ◽

10.1182/blood.v114.22.2175.2175 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2175-2175

Author(s):

Jean-Max Pasquet ◽

Romain Gioia ◽

Claire Drullion ◽

Valerie Lagarde ◽

Cedric Leroy ◽

...

Keyword(s):

Tyrosine Kinase ◽

Cell Line ◽

Tyrosine Kinases ◽

Kinase Activity ◽

Resistant Cell ◽

Resistant Cell Line ◽

Tyrosine Kinase Activity ◽

Tyrosine Residues ◽

Lyn Kinase ◽

Resistant Cells

Abstract Abstract 2175 Poster Board II-152 Targeting the tyrosine kinase activity of Bcr-Abl is an attractive therapeutic strategy in Chronic Myeloid Leukemia (CML) and in Bcr-Abl positive Acute Lymphoblastic Leukemia. Whereas imatinib, a selective inhibitor of Bcr-Abl tyrosine kinase, is now used in frontline therapy for CML, second generation inhibitors such as nilotinib or dasatinib have been developed for the treatment of imatinib-resistant or –intolerant disease. We have shown that one of the mechanisms of resistance to nilotinib is an increasing expression of the p53/56 Lyn kinase, both at mRNA and protein level in cell lines. This result was confirmed in vivo in nilotinib-resistant CML patients (Mahon et al. Cancer Res., 2008, 68(23):9809-16.). To elucidate Lyn mediated-nilotinib resistance, a phosphoproteomic study was performed by Stable Isotope Labelling with Amino acid in Cell culture (SILAC) which highlights the potential role of downstream tyrosine kinases. Among different candidate proteinsThe Spleen tyrosine kinase Syk and the UFO family receptor tyrosine kinase Axl were the most relevant in the nilotinib resistant cell line as compared to the sensitive counterpart. Syk hyperphosphorylation was confirmed in the nilotinib resistant cell line using western blot at least on tyrosine residues Y323 and Y525/526, two critical tyrosine residues respectively involved in Lyn-mediated Syk phosphorylation and autophosphorylation-associated Syk activation. Lyn interacts with Syk as detected in Syk immunoprecipitates in nilotinib resistant cells. Furthermore, Syk-Lyn interaction is inhibited by dasatinib suggesting the requirement of Lyn kinase activity and Syk phosphorylation. Targeting Syk expression in nilotinib resistant cells by siRNA or tyrosine kinase activity by pharmacological inhibitors leads respectively to a partial (35%) or to a full restoration of nilotinib sensitivity. Moreover, the identification of Axl by SILAC is correlated to a 9 fold increase of its level of expression in the resistant cell line and the inhibition of Axl tyrosine kinase activity decreases proliferation of both nilotinib sensitive and resistant CML cells. All together these results disclose a new pathway for tyrosine kinase inhibitors resistance in CML involving at least the two Lyn downstream tyrosine kinases Syk and Axl. Disclosures: Mahon: Amgen: Honoraria; Novartis Pharma: Consultancy, Honoraria, Research Funding; Alexion: Consultancy, Honoraria.

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