Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously shown that in Chinese hamster ovary (CHO) cells, a mutant cell line with a defective regulatory subunit (RI) for the cAMP-dependent protein kinase (Abraham et al: Mol. Cell. Biol., 7:3098-3106, 1987), and a transfectant cell line expressing the same mutant kinase, showed increased sensitivity to a number of drugs that are known to be substrates for the multidrug transporter (P-glycoprotein). In the current study we have investigated the mechanism by which cAMP-dependent protein kinase controls drug resistance. We report here that the sensitivity of the kinase defective CHO cell lines to multiple drugs results from decreased RNA levels for the multidrug-resistance gene. Similar results were obtained with mouse Y1 adrenal cells. Wild-type Y1 cells had high levels of P-glycoprotein due to expression of both the mdr1b and mdr2 genes, whereas the cAMP-dependent protein kinase mutant Kin 8 cells had decreased RNA levels for these genes. A Kin 8 transfectant with restored cAMP-dependent protein kinase activity recovered mdr expression, indicating a cause and effect relationship between the protein kinase mutations and mdr expression. No changes in nuclear run-off assays could be detected, suggesting a non-transcriptional mechanism of regulation. Wild-type Y1 cells are more drug sensitive despite having higher levels of P-glycoprotein than the mutant cells. This paradoxical result may be explained by the higher rate of synthesis of steroids by the wild-type Y1 cells, which appear to be inhibitors of P-glycoprotein transport activity.
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PMID:Reduced mRNA levels for the multidrug-resistance genes in cAMP-dependent protein kinase mutant cell lines. 135 2

Using dispersed cultures of fetal rat hypothalami, we studied the effects of forskolin and the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), activators of protein kinase A and C, respectively, upon vasopressin (VP) secretion, VP mRNA expression and VP mRNA poly(A) tail length. Forskolin stimulated the VP mRNA content and peptide secretion 2.6-fold and induced an increase in the poly(A) tail length of approximately 90 nucleotides. TPA induced an increase in VP mRNA size and stimulated 1.9-fold the secretion of VP without an increase in VP mRNA content. Depolarization with potassium induced an increase in the VP peptide secreted of 2.2-fold, with no effect on the VP mRNA content or size. Increased osmolality had no effect on either VP peptide or VP mRNA. We conclude that VP expression in cultured fetal rat hypothalamic cells is regulated via both protein kinase A and protein kinase C pathways.
Mol Cell Endocrinol 1992 Jul
PMID:Regulated expression of vasopressin gene by cAMP and phorbol ester in primary rat fetal hypothalamic cultures. 135 50

The interferon-induced protein kinase DAI, the double-stranded RNA (dsRNA)-activated inhibitor of translation, plays a key role in regulating protein synthesis in higher cells. Once activated, in a process that involves autophosphorylation, it phosphorylates the initiation factor eIF-2, leading to inhibition of polypeptide chain initiation. The activity of DAI is controlled by RNA regulators, including dsRNA activators and highly structured single-stranded RNAs which block activation by dsRNA. To elucidate the mechanism of activation, we studied the interaction of DAI with RNA duplexes of discrete sizes. Molecules shorter than 30 bp fail to bind stably and do not activate the enzyme, but at high concentrations they prevent activation by long dsRNA. Molecules longer than 30 bp bind and activate the enzyme, with an efficiency that increases with increasing chain length, reaching a maximum at about 85 bp. These dsRNAs fail to activate at high concentrations and also prevent activation by long dsRNA. Analysis of complexes between dsRNA and DAI suggests that at maximal packing the enzyme interacts with as little as a single helical turn of dsRNA (11 bp) but under conditions that allow activation the binding site protects about 80 bp of duplex. When the RNA-binding site is fully occupied with an RNA activator, the complex appears to undergo a conformational change.
Mol Cell Biol 1992 Nov
PMID:Interactions between double-stranded RNA regulators and the protein kinase DAI. 135 46

P68 is a protein kinase expressed by eukaryotic cells, which is inducible by alpha interferon, and is believed to be an important factor in the regulation of viral and cellular protein synthesis. We have previously reported on a monoclonal antibody, TJ4C4, which is able to specifically detect p68 in formalin-fixed, paraffin-embedded tissue. Because of its important role in regulating cellular protein synthesis, we hypothesized that p68 expression would vary among lung neoplasms with level of differentiation and degree of biosynthetic activity. A total of 246 untreated primary pulmonary and pleural neoplasms were studied. The frequency and relative intensity of p68 expression was determined by light microscopic evaluation of ABC immunoperoxidase stained specimens. All categories of tumors studied demonstrated a spectrum of p68 expression. Expression of p68 correlated well with degree of differentiation in squamous cell carcinomas (SQCC) and acinar adenocarcinomas (AAC). Papillary adenocarcinoma (PAC) and bronchioalveolar carcinoma (BAC) expressed low levels of p68, despite their well differentiated appearance. Expression of the antigen in large cell carcinoma (LCC) was higher than that seen in either poorly differentiated AAC or SQCC. Neuroendocrine tumors generally showed low levels of p68 expression with the intermediate variant of small cell carcinoma expressing higher levels of p68 than the classic "oat cell" form (SCC). Carcinoid tumors expressed higher levels of p68 than did atypical carcinoid tumors. Mesotheliomas showed weak expression of p68, limited primarily to areas of glandular differentiation in the epithelioid form.(ABSTRACT TRUNCATED AT 250 WORDS)
Virchows Arch B Cell Pathol Incl Mol Pathol 1992
PMID:Expression of the protein kinase p-68 recognized by the monoclonal antibody TJ4C4 in human lung neoplasms. 135 15

We employed a cyclic AMP-resistant subclone of UMR 106-01 osteoblastic osteosarcoma cells (UMR 4-7) with a regulated, dominant-negative mutation of cyclic AMP-dependent protein kinase (PK-A), to examine the mechanism(s) whereby parathyroid hormone (PTH) regulates growth of these cells. Expression of a transiently transfected CAT reporter gene controlled by the cAMP response element of the rat somatostatin gene ('SST-CAT') was used to monitor PK-A activation in intact cells. Agonist-stimulated SST-CAT expression was specific for agents known to activate adenylate cyclase, required an intact cAMP response element and was specifically blocked following induction of the mutant cAMP-resistant phenotype in UMR 4-7 cells. Inhibition of the proliferation of UMR 106-01 cells by PTH, which is mimicked by forskolin and 8-bromo-cAMP, was blocked completely in mutant cyclic AMP-resistant UMR 4-7 cells. We conclude that control of proliferation in UMR 106-01 cells by PTH involves the cAMP messenger system and requires activation of PK-A.
Mol Cell Endocrinol 1992 Sep
PMID:Regulation of gene transcription and proliferation by parathyroid hormone is blocked in mutant osteoblastic cells resistant to cyclic AMP. 135 85

Messenger RNA encoding a protein kinase closely related to the catalytic subunit of skeletal muscle phosphorylase kinase has previously been isolated from a human HeLa cell cDNA library, and cross-species Northern hybridization analysis has shown that the rat homolog of this transcript is abundant in the adult testis (Hanks, S.K. (1989) Mol. Endocrinol. 3, 110-116). We now propose that the protein encoded by this transcript be designated as "PhK-gamma T." In this article, the primary structure of the rat homolog of PhK-gamma T is described, as deduced from nucleotide sequences of cDNA and genomic clones. RNase protection analysis reveals that PhK-gamma T transcripts are actually present in a wide variety of adult rat tissues, but at levels 20-100-fold less than what is observed in the testis. In the testis, transcription of the PhK-gamma T gene is initiated at multiple sites as shown by RNase protection and primer extension. Enzymatic activity of PhK-gamma T was demonstrated using renatured bacterially expressed protein. In the presence of Ca2+/calmodulin, PhK-gamma T is able to efficiently phosphorylate glycogen phosphorylase and convert it from an inactive to an active form. We conclude that PhK-gamma T represents a true isoform of phosphorylase kinase catalytic subunit.
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PMID:Molecular cloning and enzymatic analysis of the rat homolog of "PhK-gamma T," an isoform of phosphorylase kinase catalytic subunit. 137 Apr 75

In this study we report identification of six members of a protein kinase gene family from soybean (Glycine max L.). Two fully degenerate oligonucleotide primers corresponding to two conserved motifs (DLK-PENV and GTHEYLAPE) in the catalytic domains of eukaryotic protein serine/threonine kinases were used in a polymerase chain reaction (PCR) to amplify soybean cDNA. Sequence analysis showed that 28 of the PCR sequences represented six different putative protein serine/threonine kinases. These results not only demonstrate that catalytic domains of protein kinases are highly conserved between plants and other eukaryotes but also suggest that there are multiple genes encoding protein kinases in plants.
Plant Mol Biol 1992 Feb
PMID:Molecular identification of a soybean protein kinase gene family by using PCR. 137 8

We have determined the first genomic structure and characterized the mRNA and protein products of a novel vertebrate gene that encodes a calcium-binding protein with amino acid sequence identity to a protein kinase domain. The elucidation of the complete DNA sequence of this transcription unit and adjacent genomic DNA, Southern blot and polymerase chain reaction analyses of cellular genomic DNA, and examination of mRNA and protein species revealed that the calcium-binding kinase-related protein (KRP)-encoding gene is contained within the gene for a calmodulin-regulated protein kinase, myosin light-chain kinase (MLCK). The KRP gene transcription unit is composed of three exons and a 5'-flanking sequence containing a canonical TATA box motif. The TATA box, the transcription initiation site, and the first 109 nucleotides of the 5' noncoding region of the KRP mRNA correspond to an MLCK gene intron sequence. Both KRP and MLCK are produced in the same adult chicken tissue in relatively high abundance from a single contiguous stretch of genomic DNA and utilize the same reading frame and common exons to produce distinct mRNAs (2.7 and 5.5 kb, respectively) that encode proteins with dissimilar biochemical functions. There appears to be no precedent in vertebrate molecular biology for such a relationship. This may represent a mechanism whereby functional diversity can be achieved within the same vertebrate tissue by use of common exons to produce shuffled domains with identical amino acid sequences in different molecular contexts.
Mol Cell Biol 1992 May
PMID:Structure and expression of a calcium-binding protein gene contained within a calmodulin-regulated protein kinase gene. 137 15

A novel protein kinase, the Esk kinase, has been isolated from an embryonal carcinoma (EC) cell line by using an expression cloning strategy. Sequence analysis of two independent cDNA clones (2.97 and 2.85 kb) suggested the presence of two Esk isoforms in EC cells. The esk-1 cDNA sequence predicted an 857-amino-acid protein kinase with a putative membrane-spanning domain, while the esk-2 cDNA predicted an 831-amino-acid kinase which lacked this domain. In adult mouse cells, esk mRNA levels were highest in tissues possessing a high proliferation rate or a sizeable stem cell compartment, suggesting that the Esk kinase may play some role in the control of cell proliferation or differentiation. As anticipated from the screening procedure, bacterial expression of the Esk kinase reacted with antiphosphotyrosine antibodies on immunoblots. Furthermore, in in vitro kinase assays, the Esk kinase was shown to phosphorylate both itself and the exogenous substrate myelin basic protein on serine, threonine, and tyrosine residues, confirming that the Esk kinase is a novel member of the serine/threonine/tyrosine family of protein kinases.
Mol Cell Biol 1992 Jun
PMID:Multiple cDNAs encoding the esk kinase predict transmembrane and intracellular enzyme isoforms. 137 25

Using probes obtained by PCR amplification, we have isolated two cognate rice cDNAs (cdc2Os-1 and cdc2Os-2) encoding structural homologues of the cdc2+/CDC28 (cdc2) protein kinase from a cDNA library prepared from cultured rice cells. Comparison of the deduced amino acid sequences of cdc2Os-1 and cdc2Os-2 showed that they are 83% identical. They are 62% identical to CDC28 of Saccharomyces cerevisiae and much more similar to the yeast and mammalian p34cdc2 kinases than to rice R2, a cdc2-related kinase isolated previously by screening the same rice cDNA library with a different oligonucleotide probe. Southern blot analysis indicated that the three rice clones (cdc2Os-1, cdc2Os-2 and R2) are derived from distinct genes and are each found in a single copy per rice haploid genome. RNA blot analysis revealed that these genes are expressed in proliferating rice cells and in young rice seedlings. cdc2Os-1 could complement a temperature-sensitive yeast mutant of cdc28. However, despite the similarity in structure, both cdc2Os-2 and R2 were unable to complement the same mutant. Thus, the present results demonstrate the presence of structurally related, but functionally distinct cognates of the cdc2 cell cycle kinase in rice.
Mol Gen Genet 1992 May
PMID:Isolation and characterization of cDNA clones encoding cdc2 homologues from Oryza sativa: a functional homologue and cognate variants. 137 1


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