Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The c-abl proto-oncogene encodes a cytoplasmic tyrosine kinase which is homologous to the src gene product in its kinase domain and in the upstream kinase regulatory domains SH2 (src homology region 2) and SH3 (src homology region 3). The murine v-abl oncogene product has lost the SH3 domain as a consequence of N-terminal fusion of gag sequences. Deletion of the SH3 domain is sufficient to render the murine c-abl proto-oncogene product transforming when myristylated N-terminal membrane localization sequences are also present. In contrast, the human BCR/ABL oncogene of the Philadelphia chromosome translocation has an intact SH3 domain and its product is not myristylated at the N terminus. To analyze the contribution of BCR-encoded sequences to BCR/ABL-mediated transformation, the effects of a series of deletions and substitutions were assessed in fibroblast and hematopoietic-cell transformation assays. BCR first-exon sequences specifically potentiate transformation and tyrosine kinase activation when they are fused to the second exon of otherwise intact c-ABL. This suggests that BCR-encoded sequences specifically interfere with negative regulation of the ABL-encoded tyrosine kinase, which would represent a novel mechanism for the activation of nonreceptor tyrosine kinase-encoding proto-oncogenes.
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PMID:BCR first exon sequences specifically activate the BCR/ABL tyrosine kinase oncogene of Philadelphia chromosome-positive human leukemias. 200 81

Activation of the c-abl protooncogene occurs in Abelson murine leukemia virus, in Hardy-Zuckerman 2 feline sarcoma virus, and during the chromosomal translocations that generate BCR-ABL gene fusion products. To study the molecular mechanism involved in the c-abl activation, we have created a series of modifications in murine c-abl and assayed these constructs for oncogenic activity using the NIH 3T3 cell transformation assay. Our results show that amino-terminal deletions are sufficient for oncogenic activation of c-abl and high levels of oncogenic activities were generated by a deletion of 114 codons from the 5' end that deleted the SH3 region. A deletion of 53 codons from the 5' end (inclusive of deletions seen in Hardy-Zuckerman 2 feline sarcoma virus and BCR-ABL gene products) that retains the SH3 region of c-abl resulted in the generation of low levels of transforming activity. This transforming potential was substantially increased with the introduction of a G----A point mutation in codon 832 that is present in v-abl. The point mutation was found to affect the secondary structure and the tyrosine kinase activity of the mutant gene products.
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PMID:Activation of murine c-abl protooncogene: effect of a point mutation on oncogenic activation. 216 50

Chronic myelogenous leukemia (CML) is associated with the reciprocal translocation of a region of chromosome 22 called BCR with the c-abl gene of chromosome 9.5' coding sequences from the BCR gene are spliced in-frame to the second exon of the ABL gene to produce a CML-specific 8.5 kilobase message which encodes the BCR-ABL hybrid protein P210. To definitively identify and characterize the normal BCR gene product, sequences from BCR cDNA clones were used to reconstitute the coding portion of the normal message in retroviral and bacterial transcription vectors. The normal BCR gene product was demonstrated to be a phosphoprotein of 160 kilodaltons by in vitro translation and immunoprecipitation from lysates of NIH3T3 lines expressing BCR retroviruses. Whereas BCR-homologous RNA levels in these cell lines were increased 50 fold, BCR protein levels increased only 2 to 10 fold depending on the presence or absence of BCR-specific 5' and 3' untranslated regions. We observe a kinase activity associated with this protein but we do not observe morphological transformation of NIH3T3 cells as a result of its overproduction.
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PMID:Structural characterization of the BCR gene product. 265 72

In chronic myeloid leukemia (CML) the proto-oncogene c-abl from chromosome 9 q34 is translocated to the breakpoint cluster region (bcr) gene on chromosome 22 q11. This translocation results in a BCR-ABL fusion gene, which encodes chimeric fusion oncoproteins p210BCR-ABL. Here we demonstrate that a peptide with joining region sequence ATGFKQSSKALQRPVAS (eight amino acids (aa) encoded by BCR exon 3; one novel lysine, encoded by the fusion codon; eight aa encoded by ABL exon 2) is immunogenic to human T cells. Primary immune response induction with this peptide resulted in a HLA DR2(DRB1*1501) restricted CD4+ BCR-ABL peptide specific T cell line P1. Responses of P1 were negatively affected by individual aa replacement by alanine at eight aa positions within the 17mer peptide (F4, K5, Q6, K9, L11, Q12, R13, P14). These findings were supported by experiments with a panel of overlapping 11mer b3a2 peptides. Only two of these peptides with an aa sequence encompassing all residues which could not be replaced by alanine induced P1 proliferation. Since presentation of cytosolic oncoproteins as peptides by DR molecules has been observed, the present findings provide a possible explanation for post interferon-alpha persisting remissions in spite of the presence of BCR-ABL PCR positive progenitors.
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PMID:Recognition of peptides corresponding to the joining region of p210BCR-ABL protein by human T cells. 764 23

BCR-ABL is a chimeric oncogene generated by translocation of sequences from the c-abl protein-tyrosine kinase gene on chromosome 9 into the BCR gene on chromosome 22. Alternative chimeric proteins, p210BCR-ABL and p190BCR-ABL, are produced that are characteristic of chronic myelogenous leukemia and acute lymphoblastic leukemia, respectively. Their role in the etiology of human leukemia remains to be defined. Transformed murine hematopoietic cells can be used as a model of BCR-ABL function since these cells can be made growth factor independent and tumorigenic by the action of the BCR-ABL oncogene. We show that the BCR-ABL oncogenes prevent apoptotic death in these cells by inducing a Bcl-2 expression pathway. Furthermore, BCR-ABL-expressing cells revert to factor dependence and nontumorigenicity after Bcl-2 expression is suppressed. These results help to explain the ability of BCR-ABL oncogenes to synergize with c-myc in cell transformation.
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PMID:Tumorigenic activity of the BCR-ABL oncogenes is mediated by BCL2. 777 99

The bcr-abl oncogene is a fusion gene resulting from a reciprocal translocation which forms the hallmark of chronic myeloid leukemia (CML). Antisense oligonucleotides complementary to the two possible mRNA breakpoints were found to inhibit cell growth of CML patient cells and cell lines, but doubt exists about their specificity. In order to test the specificity, phosphorothioate and 3' phosphorothioate capped antisense BCR-ABL oligonucleotides of different length were used. Stability, cellular uptake of oligonucleotides and effect on cell growth were studied in two CML cell lines, BV173 and LAMA-84. Phosphorothioate antisense BCR-ABL oligonucleotides were most stable, showed the highest uptake and induced cell death in BV173 but not in LAMA-84 cells. We selected the most effective antisense oligonucleotide for further analysis. The BV173 and LAMA-84 cell lines do not express the normal c-abl protein, we therefore used a c-abl specific monoclonal antibody for the detection of p210bcr-abl expression by flow cytometry. Dead cells found after treatment were gated out of analysis. Although BCR-ABL antisense oligonucleotides can induce apoptosis, no reduction of p210bcr-abl levels could be detected in living cells after treatment with antisense oligonucleotides. We conclude that antisense mediated inhibition of translation of mRNA into p210bcr-abl is not the mechanism responsible for the induction of apoptosis in cell line BV173.
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PMID:Phosphorothioate BCR-ABL antisense oligonucleotides induce cell death, but fail to reduce cellular bcr-abl protein levels. 784 6

Mutants and fusion products of the c-abl gene were used to define some of the molecular requirements for rapid plasmacytoma (PC) and pre-B-lymphoma induction in pristane-treated N-myc transgenic BALB/c mice. A-MuLV induced PCs in 21 of 25 mice with a mean post-pristane latency period of 46 +/- 9 days, compared to 134 +/- 25 days in controls exposed to pristane alone. delta XB, a mutant of type IV c-abl with a deletion of the SH3 domain, was equally effective in inducing PCs in 7 of 7 mice with a latency period of 49 +/- 7 days, indicating that gag sequences are not required for rapid PC induction. The delta XB delta Nar mutant that carried a large C-terminal deletion in addition showed only a negligible activity, if any, suggesting that PC acceleration requires the C-terminal domain in the same way as lymphoid transformation and in contrast to fibroblast transformation. BCR-ABL fusion constructs encoding an 185-kDa protein as in acute leukemia, or a 210-kDa protein as in chronic myelocytic leukemia (CML), did not accelerate pristane-induced PC development in the N-myc transgenic mice, in contrast to their known ability to immortalize lymphoid cells in vitro. Only one of 14 non-transgenic littermates developed a pre-B lymphoma after A-MuLV infection, and none of 10 normal littermates infected with delta XB virus developed a construct-carrying tumor. This result suggests that PC acceleration is due to co-operative interaction of the N-myc transgene and activated abl. Infection of N-myc transgenic bone marrow or spleen cells with A-MuLV in vitro led to the outgrowth of pre-B lymphomas after transplantation to pristane-treated BALB/c recipients. The lymphoma-inducing activity of A-MuLV depends on its high titer, since diluted A-MuLV or the lower-titered delta XB induced only PCs under the same conditions. The v-abl, delta XB and BCR-ABL-carrying viruses generated immortalized lymphoblastoid lines in vitro, regardless of the presence of the N-myc transgene, suggesting that lymphoid transformation is a direct function of appropriate abl sequences in contrast to PC acceleration.
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PMID:Molecular requirements for rapid plasmacytoma and pre-B lymphoma induction by Abelson murine leukemia virus in myc-transgenic mice. 801 9

Activation of the c-abl protooncogene occurs in Abelson murine leukemia virus, Hardy-Zuckerman-2 feline sarcoma virus, and during the chromosomal translocation that generates the BCRABL fusion gene. The three genes exhibit varying degrees of transforming activity; the two viral genes transform NIH-3T3 cells in vitro, whereas the BCRABL gene is incapable of transforming these cells. To determine whether genetic alterations can enhance the transforming potential of the BCRABL gene, we employed genetic selection techniques which led to the isolation of a mutant form of the BCRABL gene with high levels of fibroblastic transforming activity. Molecular analysis of this clone shows that it suffered a deletion of 3' ABL sequences and their replacement with a cellular sequence of unknown origin, termed X. This tripartite gene is capable of inducing 35 foci/10 ng of DNA. Deletion of 3' ABL sequences analogous to that seen in the activated BCRABL protein without the addition of X yields 5 foci/100 ng of DNA. These results suggest that carboxyl-terminal truncations unmask the fibroblastic transforming activity of the BCRABL gene product and the addition of X sequences dramatically enhances this transforming potential, indicating a dominant contribution by the X reading frame.
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PMID:Structural alterations in the carboxyl-terminal domain of the BCRABL gene product activate its fibroblastic transforming potential. 810 23

The Philadelphia chromosome, detected in virtually all cases of chronic myelogenous leukemia, is formed by a reciprocal translocation between chromosomes 9 and 22 that fuses BCR encoded sequences upstream of exon 2 of c-ABL. This oncogene produces a fusion protein, p210BCR-ABL, in which the ABL tyrosine kinase activity is elevated. This elevated kinase activity is essential for transformation, but the mechanisms involved are unknown. To investigate p210BCR-ABL function we constructed a model system in which the tyrosine kinase activity of p210BCR-ABL was inducible. Two amino acid substitutions, Arg to His at amino acid 457 and Tyr to His at amino acid 469 of c-abl, modeled on mutations known to render v-src temperature-sensitive for tyrosine kinase activity, were introduced into p210BCR-ABL. This mutant was characterized in an IL-3 growth factor dependent murine myeloid cell line, 32Dc13. Cell lines expressing the temperature-sensitive mutant remained factor dependent at the non-permissive temperature, but at the permissive temperature displayed a marked reduction in cell death in the absence of growth factor and an exaggerated proliferative response to low levels of IL-3. Both the kinase activity of the mutant and the levels of tyrosine phosphorylated proteins are increased in the temperature-sensitive mutant at the permissive temperature. Further, tyrosine phosphorylation of potential substrates of the p210BCR-ABL tyrosine kinase, p120 rasGAP and its associated proteins of p190 and p62, only occurs at the permissive temperature in cells expressing the temperature-sensitive mutant.
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PMID:Use of a temperature-sensitive mutant to define the biological effects of the p210BCR-ABL tyrosine kinase on proliferation of a factor-dependent murine myeloid cell line. 830 74

In human T-lymphocytes the Src family protein tyrosine kinase p59(fyn) associates with three phosphoproteins of 43, 55, and 85 kDa (pp43, pp55, and pp85). Employing a GST-Fyn-Src homology 2 (SH2) domain fusion protein pp55 was purified from lysates of Jurkat T-cells. Molecular cloning of the pp55 cDNA reveals that the pp55 gene codes for a so far nondescribed polypeptide of 359 amino acids that comprises a pleckstrin homology domain, a C-terminal SH3 domain, as well as several potential tyrosine phosphorylation sites, among which one fulfills the criteria to bind Src-like SH2 domains with high affinity. Consistent with this observation, pp55 selectively binds to isolated SH2 domains of Lck, Lyn, Src, and Fyn but not to the SH2 domains of ZAP70, Syk, Shc, SLP-76, Grb2, phosphatidylinositol 3-kinase, and c-abl in vitro. Based on these properties the protein was termed SKAP55 (src kinase-associated phosphoprotein of 55 kDa). Northern blot analysis shows that SKAP55 mRNA is preferentially expressed in lymphatic tissues. SKAP55 is detected in resting human T-lymphocytes as a constitutively tyrosine phosphorylated protein that selectively interacts with p59(fyn). These data suggest that SKAP55 represents a novel adaptor protein likely involved in Fyn-mediated signaling in human T-lymphocytes.
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PMID:Molecular cloning of SKAP55, a novel protein that associates with the protein tyrosine kinase p59fyn in human T-lymphocytes. 919 99


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