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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Activation of cyclin-dependent kinases (CDKs) by interaction with cyclins regulates progression through cell cycle checkpoints. This process is counterbalanced by
CDK
inhibitors (CDKIs), which can inhibit progression through the cell cycle. Because CDKI expression acts to inhibit cellular proliferation, CDKIs may have a role as tumor suppressors. One class of CDKIs, characterized by the presence of
ankyrin
repeats, has at least four members (p15INK4B), p16INK4, p18, and p19). Two of these, p15INK4B, p16INK4, have been mapped to chromosome 9p21, a region of frequent loss in a wide variety of cancers. Alterations of p16INK4 have been detected in various tumors and cell lines. We analyzed p15INK4B, p16INK4, and p18 alterations in 52 osteosarcomas (including 11 explants), and 23 other various sarcomas. Single-stranded conformation polymorphism analysis [polymerase chain reaction (PCR-SSCP)] of the coding regions of these CDKI genes detected a missense mutation of p16INK4 exon 1 in one soft tissue sarcoma. Southern blotting detected complete deletion of p15INK4B and p16INK4 genes in osteosarcomas from 2 patients and a soft tissue sarcoma from another individual. Loss of heterozygosity (LOH) at chromosome 9p21 was observed with a microsatellite probe closely linked to the INK4 genes in the latter case. Deletions of both p15INK4B and p16INK4 genes were detected in five of eight osteosarcoma cell lines. By contrast, no alterations of p18 were detected in any sample. Together these data suggest that alterations of the p15INK4B and p16INK4 genes, but not p18, may occur in approximately 5% of sarcomas. However, deletions of the p15INK4B and P16INK4 genes are frequent in osteosarcoma cell lines and probably have a role in tumor cell growth in culture. Notably, all seven detectable deletions involved both p15INK4B and p16INK4 genes, suggesting that both contribute individual tumor suppressor activity.
...
PMID:Alterations of the p15, p16,and p18 genes in osteosarcoma. 860 40
The
serine/threonine protein kinase
Raf-1
is a component of a conserved intracellular signaling cascade that controls responses to various extracellular stimuli. Transcription from several promoters, including the oncogene-responsive element in the polyomavirus enhancer, the c-fos promoter, as well as other AP-1- and Ets-dependent promoters, can be induced by
Raf-1
kinase. Previously, we have shown that activated
Raf-1
kinase transactivates the human immunodeficiency virus type 1 (HIV-1) long terminal repeat and have identified the NF-kappaB binding motif as a
Raf-1
-responsive element (RafRE). We now report that
Raf-1
kinase-induced transactivation from the HIV RafRE involves the purine-rich-repeat-binding protein (GABP), which is composed of two distinct subunits (alpha and beta). GABP alpha is an Ets oncogene-related DNA-binding protein, and GABP beta contains four
ankyrin
-like repeats that have been shown to be essential in protein-protein interactions. In electrophoretic mobility shift assays using nuclear extracts from human Jurkat T cells, a protein-DNA complex which was supershifted with antiserum against GABP alpha and GABP beta was observed. Purified recombinant GABP alpha and beta interact with the HIV RafRE as judged from DNA binding assays. Cotransfection experiments with GABP alpha and beta and
Raf-1
kinase demonstrate synergistic transactivation of the HIV-1 promoter. Point mutations in the HIV RafRE abolished the
Raf-1
kinase as well as GABP alpha- and beta-induced transactivation. The observed
Raf-1
-GABP synergism presumably involves phosphorylation of GABP subunits, as treatment of cells with
Raf-1
kinase activators serum and 12-O-tetradecanoylphorbol-13-acetate increases phosphorylation of GABP in vivo. However, GABP is not a target of
Raf-1
kinase; instead, it is a substrate of mitogen-activated protein kinase (MAPK/ERK), since in vitro phosphorylation of GABP alpha and beta was achieved by the reconstituted
protein kinase
cascade but not with purified
Raf-1
or MEK. These results suggest that
Raf-1
kinase- induced activation of the HIV-1 promoter is mediated by the classical cytoplasmic cascade resulting in MAPK/ERK-mediated phosphorylation of GABP alpha and beta. Because the HIV RafRE corresponds to a region within the promoter which is essential for regulation of HIV-1 expression, the data indicate that in addition to NK-kappaB, GABP transcription factors are important for induced expression of HIV.
...
PMID:Raf-1 kinase targets GA-binding protein in transcriptional regulation of the human immunodeficiency virus type 1 promoter. 864 52
At a point in late G1 termed Start, yeast cells enter S phase, duplicate their spindle pole bodies, and form buds. These events require activation of Cdc28 kinase by G1 cyclins. Swi4 associates with Swi6 to form the SCB-binding factor complex which activates G1 cyclin genes CLN1 and CLN2 in late G1. In G2 and M phases, the transcriptional activity of SCB-binding factor is repressed by the mitotic Clb2/Cdc28 kinase. Mbp1, a transcription factor related to Swi4, forms the MCB-binding factor complex with Swi6, which activates DNA synthesis genes and S-phase cyclin genes CLB5 and CLB6 in late G1. Clb2/Cdc28 kinase is not required for the repression of MCB-binding factor transcriptional activity in G2 and M phase. We show here that the Swi4 carboxy terminus is sufficient for interaction with Swi6 in vitro. A carboxy-terminal domain of Swi6 is required and sufficient for interaction with Swi4. The carboxy terminus of Mbp1 is sufficient for interaction with Swi6, and the carboxy terminus of Swi6 is required for interaction with Mbp1. By coimmunoprecipitation, we show that Swi4 but not Mbp1 interacts with Clb2/Cdc28 kinase in vivo during the G2 and M phases of the cell cycle. We demonstrate that the
ankyrin
repeats of Swi4 mediate the interaction with Clb2/Cdc28 kinase. The
ankyrin
repeats constitute a domain by which a cell cycle-specific transcription factor can interact with
cyclin-dependent kinase
complexes, thus enabling it to link its transcriptional activity to cell cycle progression.
...
PMID:The Saccharomyces cerevisiae Start-specific transcription factor Swi4 interacts through the ankyrin repeats with the mitotic Clb2/Cdc28 kinase and through its conserved carboxy terminus with Swi6. 864 72
A phosphatidylinositol (PI) 4-kinase cDNA was cloned from a rat brain cDNA library. This cDNA encoded a protein of 2041 amino acids with a calculated molecular weight of 231,317. The deduced amino acid sequence shared the identity of 52.3 and 34.4% in the presumed catalytic domain with two yeast PI 4-kinases, STT4 and PIK1, respectively, and showed 31.7% identity to p110alpha subunit of rat PI 3-kinase in the same domain. In addition, a 3' half coding region of the present cDNA was 89.6% identical to and its deduced amino acid sequence was 98.2% identical to the sequence for P14Kalpha, a recently reported human PI 4-kinase of type II, suggesting that P14Kalpha is an alternative form of the present PI 4-kinase molecule. The present cDNA contained sequences encoding the
ankyrin
repeat domain, lipid kinase unique domain, pleckstrin homology domain, presumed lipid kinase/
protein kinase
homology domain, proline-rich region, and SH3 domain. By examining PI kinase activity in transfected COS-7 cells using the epitope tag immunoprecipitation as well as the conventional way, the product phosphatidylinositol phosphate was identified as phosphatidylinositol 4-phosphate but not phosphatidylinositol 3-phosphate. This PI 4-kinase activity was markedly enhanced in the presence of Triton X-100 but relatively insensitive to inhibition by adenosine. By epitope tag immunohistochemistry, the immunoreactivity for this PI 4-kinase molecule was largely localized in close association with the membranes of the Golgi vesicles and vacuoles. By in situ hybridization analysis, the expression of mRNA for this PI 4-kinase was evident throughout the gray matter of entire brain with higher expression intensity in fetal brain. These data imply that this novel PI 4-kinase is involved in some processes essential to neuronal differentiation and maturation including the synaptogenesis and synaptic plasticity.
...
PMID:Cloning, expression, and localization of 230-kDa phosphatidylinositol 4-kinase. 866 89
Activation of the nuclear transcription factor-kappaB is an early event in endothelial activation. NF-kappaB activation is regulated by the inducible phosphorylation and subsequent degradation of the inhibitory subunit IkappaB-alpha. We identified two discrete kinases of approximately 36 and 41 kDa in the cytoplasm of human umbilical vein endothelial cells that specifically bind to and phosphorylate the IkappaB-alpha subunit. IkappaB-alpha kinase activity is transiently elevated following treatment with either tumor necrosis factor alpha, interleukin-1beta, or bacterial lipopolysaccharides and precedes activation of either mitogen-activated kinase or Jun kinase. Furthermore, activation of the IkappaB-alpha kinases precedes both the appearance of hyperphosphorylated IkappaB-alpha and its subsequent degradation, as well as the translocation of NF-kappaB to the nucleus. Deletion mutagenesis of the IkappaB-alpha polypeptide revealed that these kinases bind in or around the
ankyrin
repeat domains and phosphorylate residues within the C terminus. These kinases, however, were not identical to
casein kinase II
and displayed a pharmacologic profile distinct from other known kinases. These kinases may represent components of a signal transduction pathway regulating IkappaB-alpha levels in vascular endothelium.
...
PMID:Identification of signal-induced IkappaB-alpha kinases in human endothelial cells. 870 71
The specificity of the catalytic subunit of protein phosphatase-1 (PP1c) is modified by regulatory subunits that target it to particular subcellular locations. Here, we identify PP1c-binding domains on GL and GM, the subunits that target PP1c to hepatic and muscle glycogen, respectively, and on M110, the subunit that targets PP1c to smooth muscle myosin. GM-(G63-T93) interacted with PP1c and prevented GL from suppressing the dephosphorylation of glycogen phosphorylase, but it did not dissociate GL from PP1c or affect other characteristic properties of the PP1GL complex. These results indicate that GL contains two PP1c-binding sites, the region which suppresses the dephosphorylation of glycogen phosphorylase being distinct from that which enhances the dephosphorylation of glycogen synthase. At higher concentrations, GM-(G63-N75) had the same effect as GM-(G63-T93), but not if Ser67 was phosphorylated by cyclic-AMP-dependent
protein kinase
. Thus, phosphorylation of Ser67 dissociates GM from PP1c because phosphate is inserted into the PP1c-binding domain of GM. M110-(M1-E309) and M110-(M1-F38), but not M110-(D39-E309), mimicked the M110 subunit in stimulating dephosphorylation of the smooth muscle myosin P-light chain and heavy meromyosin in vitro. However, in contrast to the M110 subunit and M110-(M1-E309), neither M110-(M1-F38) nor M110-(D39-E309) suppressed the PP1c-catalysed dephosphorylation of glycogen phosphorylase. These observations suggest that the region which stimulates the dephosphorylation of myosin is situated within the N-terminal 38 residues of the M110 subunit, while the region which suppresses the dephosphorylation of glycogen phosphorylase requires the presence of at least part of the region 39-309 which contains seven
ankyrin
repeats. M110-(M1-F38) displaced GL from PP1c, while GM-(G63-T93) displaced M110 from PP1c in vitro. These observations indicate that the region(s) of PP1c that interact with GM/GL and M110 overlap, explaining why different forms of PP1c contain just a single targetting subunit.
...
PMID:Identification of protein-phosphatase-1-binding domains on the glycogen and myofibrillar targetting subunits. 870 35
Induction of cell proliferation by mitogen or growth factor stimulation leads to the specific stimulation or repression of a large number of genes. To better understand differentiated epithelial cell growth regulation, we have initiated a study to identify genes which are regulated by the thyrotropin-dependent mitogenic pathway in dog thyroid cells. A thyroid cDNA library was prepared from a methimazole and propylthiouracil-treated dog and differentially screened with probes derived from control or stimulated thyroids. Among 19 clones isolated, 6 encode known proteins (inwardly rectifying potassium channel, nucleosome assembly protein, ribosomal protein L7, elongation factor 1alpha, non-muscle myosin light chain, and heat shock protein 90beta). The 13 others correspond to proteins whose function is unknown. Among them, 5 correspond to mRNAs whose expression was modulated by mitogenic stimulation of thyrocytes in primary culture. A preliminary characterization of two of these cDNAs is reported: clone 5, which might represent a novel, atypical
protein kinase
, and clone 3, which contains
ankyrin
-like repeats, suggesting that it might interact with other proteins.
...
PMID:Identification and characterization of novel genes modulated in the thyroid of dogs treated with methimazole and propylthiouracil. 891 Apr 71
In response to phosphorus limitation, the fungus Neurospora crassa synthesizes a number of enzymes that function to bring more phosphate into the cell. The NUC-2 protein appears to sense the availability of phosphate and transmits the signal downstream to the regulatory pathway. The nuc-2+ gene has been cloned by its ability to restore growth of a nuc-2 mutant under restrictive conditions of high pH and low phosphate concentration. We mapped the cloned gene to the right arm of linkage group II, consistent with the chromosomal position of the nuc-2 mutation as determined by classical genetic mapping. The nuc-2' open reading frame is interrupted by five introns and codes for a protein of 1066 amino acid residues. Its predicted amino acid sequence has high similarity to that of its homolog in Saccharomyces cerevisiae, PHO81. Both proteins contain six
ankyrin
repeats, which have been implicated in the
cyclin-dependent kinase
inhibitory activity of PHO81. The phenotypes of a nuc-2 mutant generated by repeat-induced point mutation and of a strain harboring a UV-induced nuc-2 allele are indistinguishable. Both are unable to grow under the restrictive conditions, a phenotype which is to some degree temperature dependent. The nuc-2+ gene is transcriptionally regulated. A 15-fold increase in the level of the nuc-2+ transcript occurs in response to a decrease in exogenous phosphate concentration.
...
PMID:NUC-2, a component of the phosphate-regulated signal transduction pathway in Neurospora crassa, is an ankyrin repeat protein. 891 14
Integrins are heterodimeric integral plasma membrane proteins containing extracellular, transmembrane, and cytoplasmic domains. These highly versatile receptors mediate not only cell adhesion and migration, but also the bidirectional transfer of information across the plasma membrane. The cytoplasmic domains of integrins are required for the transduction of this bidirectional information, and have recently been shown to participate in direct interactions with some novel cytoplasmic proteins, such as an
ankyrin
repeat containing
serine/threonine protein kinase
(integrin-linked kinase) and beta3 endonexin. New evidence also suggests that, via interactions with focal adhesion kinase, the integrin cytoplasmic domains can coordinate actin cytoskeletal organization and responses to growth factors. The elucidation of the signal transduction pathways activated by integrins is an intense area of investigation that has shown that integrins have some unique properties as signal transducing receptors.
...
PMID:Integrin cytoplasmic interactions and bidirectional transmembrane signalling. 893 56
Cyclin-dependent kinase inhibitors (CDKIs) can be classified into two groups based on the structure of the proteins. One group includes the p21 (CIP1, WAF1, CAP20), p27 (Kip1), and p57 (Kip2) CDKIs, which contain a homologous amino-terminal
cyclin-dependent kinase
(cdk) inhibitory domain. The p16 (INK4A), p15 (INK4B), and p18 (INK4C) CDKIs, which have an
ankyrin
repeat motifs, belong to the other group. The p16 and p15 CDKI genes are very frequently altered in a variety of cancers including hematopoietic malignancies. The p19 (INK4D) gene is a newly cloned CDKI which belongs to the latter group. To determine if p19 genetic alterations play a role in hematopoietic malignancies, we examined DNA from 45 childhood newly diagnosed acute lymphocytic leukemias (ALLs), 30 acute myeloblastic leukemias (AMLs), 10 chronic myelocytic leukemias (CMLs), 45 adult T cell leukemias (ATLs), 70 non-Hodgkin's lymphomas (NHLs), and 20 multiple myelomas (MM) as well as 14 ALL, 20 AML, two ATL, and five lymphoma cell lines. Using Southern blot analysis, one homozygous deletion of the p19 gene was detected in a human immunodeficiency virus (HIV)-related Burkitt-like lymphoma sample. No point mutations in any of the samples were found by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. Our investigation suggests that alterations of p19 do not play an important role in the development of most hematopoietic malignancies.
...
PMID:Alterations of the cyclin-dependent kinase inhibitor p19 (INK4D) is rare in hematopoietic malignancies. 894 28
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