Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently we described the establishment in culture and the immunophenotypic and functional characteristics of a human T-leukemia line TALL-103/2 derived from the T-cell receptor (TCR)-gamma/delta subset of T-lymphocytes. TALL-103/2 cells are absolutely dependent on interleukin 2 (IL-2) for their growth and survival in culture and thus provide a model cell line for studies of IL-2 signal transduction in a TCR-gamma/delta T-cell. In this report, we focus on the regulation of SRC-family protein tyrosine kinases (PTKs) by IL-2. TALL-103/2 cells were found to contain p56-LCK, p59-FYN, p62-YES and p53/56-LYN. Stimulation of growth factor-deprived TALL-103/2 cells with IL-2, however, induced increases in the relative activity only of the p56-LCK kinase. This IL-2-mediated increase in LCK kinase activity was manifested both by increased kinase autophosphorylation and by increased phosphorylation of the exogenous substrate enolase during in vitro kinase assays. Furthermore, immunoblot assays determined that the levels of p56-LCK protein were unaltered by IL-2-treatment, indicating that the measured elevations in LCK kinase activity reflected an increase in the specific activity of this PTK. In TALL-103/2 cells, IL-2 stimulated concentration-dependent increases in p56-LCK activity that displayed rapid and transient kinetics: detectable increases occurred within 1 minute after IL-2 stimulation, peaked at 10 minutes, and declined to baseline levels by 30 minutes. Treatment of TALL-103/2 cells with IL-4 abrogated IL-2-initiated proliferation, but did not inhibit IL-2-mediated activation of p56-LCK.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interleukin 4 inhibits IL-2-induced proliferation of a human T-leukemia cell line without interfering with p56-LCK kinase activation. 142 Sep 98

Unlike many other growth factor receptors, the known subunits of the receptors for the Interleukins IL-2 and IL-3 lack intrinsic tyrosine kinase activity, and yet increases in the phosphorylation of proteins on tyrosines is a rapid event in hematolymphoid cells following stimulation with these lymphokines. Here we show that IL-2 and IL-3 regulate the activity of specific members of the SRC-family of non-receptor protein tyrosine kinases (PTKs). In IL-2-dependent T-cell lines, IL-2 induced rapid and transient increases in the activity of the p56-LCK kinase without influencing the activities of other SRC-like PTKs (p59-FYN, p62-YES) in these T-lymphocytes. In contrast to IL-2's effects on p56-LCK in T-cells, studies of an IL-2-responsive cell line of the B-cell lineage that lacks p56-LCK revealed that IL-2 specifically regulates the activity of the p53/56-LYN kinase. Thus, some flexibility exists in the ability of various SRC-like PTKs to functionally couple to IL-2 signalling pathways. In several IL-3-dependent myeloid-committed leukemic cell lines, IL-3 was found to specifically regulate the activity of the p53/56-LYN kinase without affecting the activities of other SRC-like PTKs (p59/64-HCK, p59-FYN, p62-YES) in these hematopoietic cells. This finding that p53/56-LYN can be regulated by both IL-2 in B-lineage cells and IL-3 in myeloid-committed cells demonstrates that the same SRC-family PTK can participate in signal transduction events mediated via two independent receptor systems. Taken together, our findings imply that the specific combinations of lymphokine receptors and SRC-like PTKs available for coupling with those receptors are coordinately controlled during the differentiation of hematopoietic cells.
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PMID:Regulation of SRC-family protein tyrosine kinases by interleukins, IL-2, and IL-3. 160 36

The expression of C-myc p62, bcl-2, p53, PCNA and EBV-encoded LMP-1 proteins was studied by immunohistochemistry on paraffin-embedded skin specimens from 14 patients with early stage (premycotic erythema and second stage plaques) mycosis fungoides (MF), 21 patients with advanced stage MF (third stage plaques and tumors), 3 patients with Sezary's syndrome (SS) and 3 patients with pleomorphic medium and large cell cutaneous T-cell lymphomas (PML-CTCL). All 41 cases were also screened for the presence of EBV by using RNA in situ hybridization with EBER 1/2 oligonucleotides. Increased expression of C-myc p62, p53 and PCNA proteins was found in PML-CTCL and advanced stages of MF as compared to early stages of MF. These results suggest a relationship between levels of C-myc p62, p53 and PCNA proteins and aggressiveness of the cutaneous T-cell lymphomas. Furthermore, C-myc p62 and bcl-2 proteins were found to be frequently coexpressed in the present series. In view of the background information from in vitro findings and animal models that cooperation of C-myc and bcl-2 is important for lymphomagenesis, our results suggest that coexpression of these oncogenes may be implicated in the pathogenesis and/or the progression of cutaneous T-cell lymphomas. Neither LMP-1 expression nor EBV EBER l/2 transcripts were detected in our series suggesting that EBV is not involved in the pathogenesis of cutaneous T-cell lymphomas.
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PMID:Mycosis fungoides: expression of C-myc p62 p53, bcl-2 and PCNA proteins and absence of association with Epstein-Barr virus. 783 Nov 52

Hepatitis B virus is a major risk factor in human hepatocellular carcinomas. We have used protein affinity chromatography to show that the 17-kDa hepatitis B virus gene product, HBx, binds directly to the human tumor suppressor gene product, p53. Interaction of HBx with p53 did not prevent p53 from specifically binding DNA. Instead, HBx enhanced p53's oligomerization state on a DNA oligonucleotide containing a p53 response element. Optimal binding of HBx to p53 required intact p53, but weaker binding to both the N-terminal activation domain of p53 and a protein fragment containing the C-terminal DNA-binding and oligomerization domains of p53 was observed. In transient transfection experiments with human Calu-6 cells, HBx inhibited transactivation by p53 of a reporter gene containing a p53 response element. Also, HBx inhibited p53-stimulated transcription in vitro even when added to the reaction mixture after the formation of the preinitiation complex. Interaction of HBx with p53 did not prevent the activation domain of p53 from binding two general initiation factors, the TATA-box binding protein subunit of TFIID and the p62 subunit of TFIIH. To explain these results, we propose that localization of HBx to a promoter by interaction with DNA-bound p53 enables a repression domain in HBx to directly contact the basal transcription machinery and thereby repress transcription.
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PMID:Direct interaction of the hepatitis B virus HBx protein with p53 leads to inhibition by HBx of p53 response element-directed transactivation. 785 26

Acidic transcriptional activation domains function well in both yeast and mammalian cells, and some have been shown to bind the general transcription factors TFIID and TFIIB. We now show that two acidic transactivators, herpes simplex virus VP16 and human p53, directly interact with the multisubunit human general transcription factor TFIIH and its Saccharomyces cerevisiae counterpart, factor b. The VP16- and p53-binding domains in these factors lie in the p62 subunit of TFIIH and in the homologous subunit, TFB1, of factor b. Point mutations in VP16 that reduce its transactivation activity in both yeast and mammalian cells weaken its binding to both yeast and human TFIIH. This suggests that binding of activation domains to TFIIH is an important aspect of transcriptional activation.
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PMID:Binding of basal transcription factor TFIIH to the acidic activation domains of VP16 and p53. 793 17

Cross-linking membrane Ig (mIg) on B cells stimulates tyrosine phosphorylation of proteins involved in signal transduction including the mIg-associated proteins Ig-alpha and Ig-beta, the tyrosine kinases p53/p56lyn, p55blk, p59fyn, and PTK72, phosphatidylinositol 3-kinase, phospholipase C gamma 1 and gamma 2, and the mitogen-activated protein kinase. We now show that the p21ras GTPase-activating protein (GAP) is also a substrate for mIg-activated tyrosine kinases. p21ras is a key regulator of cell growth and GAP may act as both a regulator of p21ras activity and as a downstream effector of p21ras. We found that mIg cross-linking caused a rapid increase in tyrosine phosphorylation of GAP in the immature B cell line WEHI-231, the mature B cell lines BAL 17 and Daudi, and the IgG-bearing B cell line A20. In fibroblasts, tyrosine kinase activation causes GAP to associate with two other tyrosine-phosphorylated proteins, p62 and p190, which have homologies to an RNA-binding protein and a transcriptional repressor, respectively. Similarly, mlg cross-linking induced the association of GAP with a 62-kDa tyrosine-phosphorylated protein in BAL 17, WEHI-231, and Daudi cells. Anti-Ig treatment also increased the amount of a 190-kDa tyrosine-phosphorylated protein associated with GAP in WEHI-231 and Daudi cells. After separation by SDS-PAGE and transfer to nitrocellulose, the tyrosine-phosphorylated p62 and p190 present in anti-GAP immunoprecipitates from B cells were capable of binding radiolabeled recombinant GAP, as previously reported for the GAP-associated p62 and p190 from fibroblasts. The amount of p62 that could be detected in this way after immunoprecipitation with antiphosphotyrosine antibodies was much greater from anti-IgM-treated BAL 17 cells than from unstimulated BAL 17 cells. This probably reflects anti-Ig-induced tyrosine phosphorylation of p62. In any case, GAP, p62, and/or p190 may be involved in signal transduction by mIg in B cells.
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PMID:Targets of B lymphocyte antigen receptor signal transduction include the p21ras GTPase-activating protein (GAP) and two GAP-associated proteins. 841 71

The p53 tumour suppressor is mutated in the majority of human tumours. p53's proposed role as the guardian of the genome is reflected in its multiple effects on transcription genome stability, cell growth and survival. We show that p53 interacts both physically and functionally with the TFIIH complex. There are multiple protein-protein contacts, involving two regions of p53 and three subunits of TFIIH, ERCC2 (XPD), ERCC3 (XPB) and p62. p53 and its C-terminus (amino acids 320-393) inhibit both of the TFIIH helicases and in vitro transcription in the absence of TFIIH. Transcription inhibition is overcome by TFIIH. The N-terminal region of p53 (1-320), lacking the C-terminus, is inactive on its own, yet apparently affects the activity of the C-terminus in the native protein. Interestingly, mutant p53s that are frequently found in tumours are less efficient inhibitors of the helicases and transcription. We hypothesize that the interactions provide an immediate and direct link for p53 to the multiple functions of TFIIH in transcription, DNA repair and possibly the cell cycle.
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PMID:Functional interactions between p53 and the TFIIH complex are affected by tumour-associated mutations. 861 85

Phosphorylation is believed to be one of the mechanisms by which p53 becomes activated or stabilized in response to cellular stress. Previously, p53 was shown to interact with three components of transcription factor IIH (TFIIH): excision repair cross-complementing types 2 and 3 (ERCC2 and ERCC3) and p62. This communication demonstrates that p53 is phosphorylated by the TFIIH-associated kinase in vitro. The phosphorylation was found to be catalyzed by the highly purified kinase components of TFIIH, the CDK7-cycH-p36 trimeric complex. The phosphorylation sites were mapped to the C-terminal amino acids located between residues 311 and 393. Serines 371, 376, 378, and 392 may be the potential sites for this kinase. Phosphorylation of p53 by this kinase complex enhanced the ability of p53 to bind to the sequence-specific p53-responsive DNA element as shown by gel mobility shift assays. These results suggest that the CDK7-cycH-p36 trimeric complex of TFIIH may play a role in regulating p53 functions in cells.
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PMID:The CDK7-cycH-p36 complex of transcription factor IIH phosphorylates p53, enhancing its sequence-specific DNA binding activity in vitro. 931 50

The nuclear receptor hepatocyte nuclear factor 4 (HNF-4) is an important regulator of several genes involved in diverse metabolic and developmental pathways. Mutations in the HNF-4A gene are responsible for the maturity-onset diabetes of the young type 1. Recently, we showed that the 24 N-terminal residues of HNF-4 function as an acidic transcriptional activator, termed AF-1 (Hadzopoulou-Cladaras, M., Kistanova, E., Evagelopoulou, C., Zeng, S. , Cladaras C., and Ladias, J. A. A. (1997) J. Biol. Chem. 272, 539-550). To identify the critical residues for this activator, we performed an extensive genetic analysis using site-directed mutagenesis. We showed that the aromatic and bulky hydrophobic residues Tyr6, Tyr14, Phe19, Lys10, and Lys17 are essential for AF-1 function. To a lesser degree, five acidic residues are also important for optimal activity. Positional changes of Tyr6 and Tyr14 reduced AF-1 activity, underscoring the importance of primary structure for this activator. Our analysis also indicated that AF-1 is bipartite, consisting of two modules that synergize to activate transcription. More important, AF-1 shares common structural motifs and molecular targets with the activators of the tumor suppressor protein p53 and NF-kappaB-p65, suggesting similar mechanisms of action. Remarkably, AF-1 interacted specifically with multiple transcriptional targets, including the TATA-binding protein; the TATA-binding protein-associated factors TAFII31 and TAFII80; transcription factor IIB; transcription factor IIH-p62; and the coactivators cAMP-responsive element-binding protein-binding protein, ADA2, and PC4. The interaction of AF-1 with proteins that regulate distinct steps of transcription may provide a mechanism for synergistic activation of gene expression by AF-1.
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PMID:Critical structural elements and multitarget protein interactions of the transcriptional activator AF-1 of hepatocyte nuclear factor 4. 979 14

In order to evaluate the involvement of c-yes and c-erbB-2 oncogene products, and p53 tumor suppressor protein in canine mammary neoplastic lesions, sections of archived paraffin-embedded samples of 79 mammary tumors were analyzed immunohistochemically using antibodies against human c-yes p62 and c-erbB-2 products and p53. These 79 tumors were divided into 2 groups: 32 benign (2 adenosis, 7 simple adenomas, 14 complex adenomas, and 9 benign mixed mammary tumors) and 47 malignant tumors (26 simple adenocarcinomas, 7 complex adenocarcinomas, 5 solid carcinomas, 2 sclerosing carcinomas, 6 malignant mixed mammary tumors, and 1 malignant myoepithelioma). As a result of immunostaining, 40.6% (13/32) of the benign tumors and 21.3% (10/47) of the malignant tumors expressed the c-Yes oncogene product, ErbB-2 expression was detected in 50% (16/32) of the benign tumors and in 19.1% (9/47) of the malignant tumors. P53 expression was detected in 16% (4/25) of the benign tumors and in 30.6% (11/36) of the malignant tumors. Co-expression of c-Yes and ErbB-2, ErbB-2 and p53, and all 3 products was detected in 6, 1 and 7 tumors, respectively.
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PMID:Immunohistochemical analysis of c-yes and c-erbB-2 oncogene products and p53 tumor suppressor protein in canine mammary tumors. 1002 59


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