Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

Avian reticuloendotheliosis virus (REV-T) is the most virulent of all retroviruses, inducing an invariably fatal leukemia in chickens with a latent period of 7-10 days. Unlike avian cells transformed by other acutely transforming viruses, lymphoid cells transformed by REV-T are immortalized. Furthermore, in vitro derived, REV-T transformed cells which do not produce virus are tumorigenic and induce lethal reticuloendotheliosis when injected into histocompatible birds. Thus REV-T transforms its target cell both in vitro and in vivo. In addition this transformation is independent of any helper virus functions. Like other acute leukemia viruses, REV-T is replication-defective and must co-replicate with a reticuloendotheliosis associated virus (REV-A). During evolution, a substantial portion of its genome has been deleted and replaced with a host-derived genetic sequence, designated v-rel. Presumably, the v-rel oncogene was transduced from a normal turkey DNA locus, c-rel. There are 9 regions of homology between c-rel and v-rel, however, several differences exist between these genes, suggesting that transformation by REV-T results from the production of an altered v-rel protein. The v-rel sequence is distinct from other known oncogenes and encodes a 57-kDa phosphoprotein. In REV-T transformed cells, this pp57v-rel protein is localized in the cytoplasm. The product of the v-rel oncogene is present at a low level, representing only about 0.003% of total methionine-labelled protein. In addition, pp57v-rel is relatively stable, having an estimated half-life of 4-10 h. The v-rel protein when purified close to homogeneity is complexed with a 40-kDa cellular phosphoprotein in transformed lymphoid cells and possesses serine kinase activity. This review discusses the molecular aspects of transformation by REV-T in the context of other oncogene-encoded proteins.
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PMID:Transformation of avian lymphoid cells by reticuloendotheliosis virus. 282 14

We have prepared site-specific antibodies toward human insulin, insulin-like growth factor-I, and epidermal growth factor receptors with chemically synthesized peptides derived from the cDNA-predicted amino acid sequences of these receptors. Two classes of antibodies were produced toward each receptor: one toward the carboxyl termini and the other against the kinase domains containing sequences homologous to the tyrosyl phosphorylation site of the product of src gene (pp60v-src). Both classes of antibodies specifically immunoprecipitated the appropriate 125I-ligand-receptor complexes and [35S]methionine-labeled receptors with almost equal potencies. Antibodies toward the kinase domains inhibited both autophosphorylation and tyrosine kinase activity of the corresponding receptors in a cell-free system, whereas antibodies toward the carboxyl termini did not. Microinjection of the kinase-inhibitory antibodies into the cytoplasm of human epidermoid carcinoma KB cells blocked the ability of the corresponding ligand to induce membrane ruffling. In contrast, these inhibitory antibodies did not block the ability of noncorresponding ligands to induce the same response. Furthermore, control immunoglobulin and antibodies toward the carboxyl termini did not block this biological response. These results support a role for the tyrosine-specific protein kinase activities of these growth factor receptors in mediating their biological effects and suggest that the regions homologous to the tyrosyl phosphorylation site of pp60v-src are important for these kinase activities both in cell-free and intact cell systems.
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PMID:Requirement for receptor-intrinsic tyrosine kinase activities during ligand-induced membrane ruffling of KB cells. Essential sites of src-related growth factor receptor kinases. 283 87

Complementary DNA to pig gastric mRNA encoding (H+ + K+)-ATPase was cloned, and its amino acid sequence was deduced from the nucleotide sequence. The enzyme contained 1034 amino acid residues (Mr. 114,285) including the initiation methionine. The sequence of pig (H+ + K+)-ATPase was highly homologous with that of the corresponding enzyme from rat, but had high degree of synonymous codon changes. Potential sites of phosphorylation by cAMP-dependent protein kinase and N-linked glycosylation sites were identified. The amino terminal region contained a lysine-rich sequence similar to that of the alpha subunit of (Na+ + K+)-ATPase, although a cluster of glycine residues was inserted into the sequence of the (H+ + K+)-ATPase. As the pig enzyme is advantageous for biochemical studies, the information of the primary structure is useful for further detailed studies.
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PMID:cDNA cloning and sequence determination of pig gastric (H+ + K+)-ATPase. 284 18

In this study, we report the isolation and characterization of a full-length cDNA clone for the hormone-inducible regulatory subunit RII beta (formerly called RII51) of type II cAMP-dependent protein kinase from a human testis cDNA library. The cloned cDNA demonstrated tissue-specific expression of RII beta mRNA in human tissues, with the highest mRNA levels in testis and ovary. The isolated human cDNA clone was 3.3 kilobases (kb) in length and contained 166 base pairs (bp) of G/C-rich 5'-noncoding sequence, an open reading frame of 1254 bp and an A/T-rich 3'-nontranslated region containing 1836 bp followed by an 89 nucleotide long poly(A)-tail. The predicted protein contains 418 amino acids including the start methionine, and the estimated mol wt of human RII beta is 53,856. The nucleotide sequence within the open reading frame and the predicted amino acid sequence of human RII beta are highly conserved compared with partial rat RII beta sequences, displaying 91% and 97% similarity, respectively. Codon preference analysis of the cloned cDNA sequence indicated that the two cAMP-binding domains and the hinge region are highly conserved through evolution, whereas the dimerization domain displayed a codon preference pattern indicative of appearance at a later stage of evolution. The isolated human cDNA detected an FSH- and cAMP-inducible mRNA of 3.2 kb in rat Sertoli cells, thus confirming that the cloned cDNA represents the hormone-inducible regulatory subunit of cAMP-dependent protein kinase. This is the first report documenting the isolation of a full-length cDNA clone for the RII beta of cAMP-dependent protein kinase.
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PMID:Molecular cloning, complementary deoxyribonucleic acid structure and predicted full-length amino acid sequence of the hormone-inducible regulatory subunit of 3'-5'-cyclic adenosine monophosphate-dependent protein kinase from human testis. 285 Nov 2

As reported previously [Vulliet et al. (1985) FEBS Lett. 182 335-339], tyrosine hydroxylase purified from rat pheochromocytoma is phosphorylated at an identical site (site A) by cyclic AMP-dependent protein kinase, the calmodulin-dependent multiprotein kinase and protein kinase C, while the calmodulin-dependent multiprotein kinase also phosphorylates another unique site (site C). Preparations of tyrosine hydroxylase purified from this source are also contaminated with traces of a fourth protein kinase which phosphorylates another unique site (site E). We have isolated tryptic peptides containing each of these sites and determined their amino acid sequences. By comparison of these data with the known cDNA sequence for rat tyrosine hydroxylase, we have been able to identify these sites as Ser-8 (site E), Ser-19 (site C), and Ser-40 (site A). In some preparations of tyrosine hydroxlyase, cyclic AMP-dependent protein kinase also phosphorylated a secondary site which was identified as ser-153. All of these phosphorylation sites are in the amino-terminal region, where there is no significant homology with the closely related enzyme, phenylalanine hydroxylase. Our data also establish that the initiator methionine is removed by post-translational processing to leave pro-2 as the amino-terminus of the mature protein. The significance of these results for the mechanism of action of extracellular signals on catecholamine biosynthesis is discussed.
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PMID:Identification of four phosphorylation sites in the N-terminal region of tyrosine hydroxylase. 287 40

We have examined the sites phosphorylated on acetyl-CoA carboxylase by three protein kinases which have been shown to inactivate the enzyme, i.e. cyclic-AMP-dependent protein kinase, acetyl-CoA carboxylase kinase-2 (ACK2, purified from rat mammary gland) and the AMP-activated protein kinase (formerly called acetyl-CoA carboxylase kinase-3, purified from rat liver). Each protein kinase phosphorylates two out of three sites (termed 1-3) which have been established by amino acid sequencing. The two sites phosphorylated by each kinase can be recovered on separate peptides, TC1 and TC2, derived by combined digestion of the native enzyme by trypsin and chymotrypsin: TC1 = Ser-2Ser(P)-Met-3Ser(P)-Gly-Leu; TC2 = Arg-Met-1Ser(P)-Phe- Cyclic-AMP-dependent protein kinase phosphorylates sites 1 and 2 exclusively, whereas the AMP-activated protein kinase phosphorylates sites 1 and 3, plus at least one other minor site. ACK2 phosphorylates site 1 and, more slowly, an unidentified site(s) within TC1. We have also established the structures of the single major phosphopeptides (T1 and C1 respectively) which are recovered by HPLC after acetyl-CoA carboxylase phosphorylated by cyclic-AMP-dependent protein kinase is digested with trypsin or chymotrypsin alone. T1 is related to TC1, and has the structure: Ser-Ser(P)-Met-Ser-Gly-Leu-His-Leu-Val-Lys. C1 is identical with TC2. We have carried out studies on the correlation of the activity of acetyl-CoA carboxylase with the occupancy of sites 1, 2 and 3 during phosphorylation by each of the three protein kinases. The results suggest that phosphorylation of site 3 is primarily responsible for the large decrease in Vmax produced by the AMP-activated protein kinase, while phosphorylation of site 1 may be primarily responsible for the increase in A0.5 for citrate and more modest depression of Vmax produced by cyclic-AMP-dependent protein kinase and ACK2. Our results emphasize that amino acid sequence information is essential in the unequivocal interpretation of data from phosphopeptide mapping experiments and allow a more complete interpretation of previous data on phosphorylation of acetyl-CoA carboxylase in intact cells. They also open the way to experiments which could establish the physiological roles of these protein kinases in the control of fatty acid synthesis.
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PMID:Identification by amino acid sequencing of three major regulatory phosphorylation sites on rat acetyl-CoA carboxylase. 290 Jan 38

1. The phorbol ester 12-O-tetradecanoyl phorbol 13-acetate (TPA) stimulates fatty acid synthesis from glucose in isolated adipocytes with a half-maximal effect at 0.72 microM. In seven batches of cells, the maximal effects of TPA and insulin were 8.5 +/- 1.1-fold and 27.1 +/- 2.1-fold respectively. Insulin also stimulated fatty acid synthesis from acetate 8.9 +/- 0.5-fold (three experiments), but TPA did not significantly increase fatty acid synthesis from this precursor. 2. In contrast to insulin, TPA treatment of isolated adipocytes did not produce an activation of acetyl-CoA carboxylase which was detectable in crude cell extracts. 3. The total phosphate content of acetyl-CoA carboxylase, isolated from adipocytes in the presence of protein phosphatase inhibitors, was estimated by 32P-labelling experiments to be 2.6 +/- 0.1 (5), 3.4 +/- 0.2 (5), and 3.8 +/- 0.2 (3) mol/mol subunit for enzyme from control, insulin- and TPA-treated cells respectively. Insulin and TPA stimulated phosphorylation within the same two tryptic peptides. 4. Purified acetyl-CoA carboxylase is phosphorylated in vitro by protein kinase C at serine residues which are recovered in three tryptic peptides, i.e. peptide T1, which appears to be identical with the peptide Ser-Ser(P)-Met-Ser-Gly-Leu-His-Leu-Val-Lys phosphorylated by cyclic-AMP-dependent protein kinase, and peptides Ta and Tb, which have the sequences Ile-Asp-Ser(P)-Gln-Arg and Lys-Ile-Asp-Ser(P)-Gln-Arg respectively, and which appear to be derived from a single site by alternative cleavages. None of these correspond to the peptides whose 32P-labelling increase in response to insulin or TPA. Peptides Ta/Tb are not significantly phosphorylated in isolated adipocytes, even after insulin or TPA treatment. Peptide T1 is phosphorylated in isolated adipocytes, but this phosphorylation is not altered by insulin or TPA. 5. These results show that TPA mimics the effect of insulin on phosphorylation, but not activation, of acetyl-CoA carboxylase, i.e. that these two events can be dissociated. In addition, phorbol ester stimulates phosphorylation of acetyl-CoA carboxylase in isolated adipocytes, but this is not catalyzed directly by protein kinase C, and acetyl-CoA carboxylase does not appear to be a physiological substrate for this kinase.
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PMID:Insulin and phorbol ester stimulate phosphorylation of acetyl-CoA carboxylase at similar sites in isolated adipocytes. Lack of correspondence with sites phosphorylated on the purified enzyme by protein kinase C. 290 Jan 39

We have reported previously that cyclic AMP-dependent protein kinase phosphorylates two sites on acetyl-CoA carboxylase (site 1: Arg-Met-Ser(P)-Phe, and site 2: Ser-Ser(P)-Met-Ser-Gly-Leu), while the AMP-activated protein kinase also phosphorylates site 1, plus site 3 (Ser-Ser-Met-Ser(P)-Gly-Leu), the latter being two residues C-terminal to site 2. We now report that prior phosphorylation of site 2 by cyclic AMP-dependent protein kinase prevents the subsequent phosphorylation of site 3 and the consequent large decrease in Vmax produced by the AMP-activated protein kinase. Similarly, prior phosphorylation of site 3 by the AMP-activated protein kinase prevents subsequent phosphorylation of site 2 by cyclic AMP-dependent protein kinase.
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PMID:Negative interactions between phosphorylation of acetyl-CoA carboxylase by the cyclic AMP-dependent and AMP-activated protein kinases. 290 Jan 58

A monospecific polyclonal antiserum to the regulatory subunit (R) of the cAMP-dependent protein kinase of Blastocladiella emersonii has been developed by immunization with purified regulatory subunit. In Western blots, the antiserum displays high affinity and specificity for the intact R monomer of Mr = 58,000, as well as for its proteolytic products of Mr = 43,000 and Mr = 36,000, even though the antiserum has been raised against the Mr = 43,000 fragment. Western blots of cell extracts prepared at different times during the life cycle of the fungus indicate that the increase in cAMP-binding activity occurring during sporulation, as well as its decrease during germination, are associated with the accumulation of the regulatory subunit during sporulation and its disappearance during germination, respectively. Pulse labeling with [35S]methionine and immunoprecipitation indicate that the accumulation of R is due to its increased synthesis during sporulation. Two-dimensional gel electrophoresis of affinity purified cell extracts obtained after [35S]methionine pulse labeling during sporulation confirms de novo synthesis of R during this stage and furthermore shows that the protein is rapidly phosphorylated after its synthesis. In vitro translation studies using RNA isolated from different stages of the life cycle followed by immunoprecipitation have shown that the time course of expression of the mRNA coding for the regulatory subunit parallels the rate of its synthesis in vivo.
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PMID:Developmental regulation of expression of the regulatory subunit of the cAMP-dependent protein kinase of Blastocladiella emersonii. 291 35

Protein phosphorylation in intact S49 mouse lymphoma cells was studied by using high-resolution two-dimensional gel electrophoresis of proteins labelled with [35S]methionine or [32P]Pi. In wild-type cells substrates for cyclic AMP-stimulatable phosphorylation exhibited high basal phosphorylation; in mutant cells deficient in activities of either cyclic AMP-dependent protein kinase or adenylate cyclase, basal phosphorylation of most of these substrates was negligible. Analysis of tryptic phosphopeptides from proteins labelled with [32P]Pi in wild-type cells suggested that identical sites were phosphorylated under conditions of both basal and hormonally elevated concentrations of cyclic AMP. These results argue that most basal phosphorylation is a consequence of partial activation of cyclic AMP-dependent protein kinase and that this activation is attributable to basal concentrations of cyclic AMP. For the intermediate filament protein vimentin, basal phosphorylation was largely at a site distinct from that stimulated by increased cyclic AMP, and basal phosphorylation was not markedly different in mutant and wild-type cells. Vimentin phosphorylated at both sites was not observed. Cyclic AMP treatment resulted in enhanced phosphorylation at the cyclic AMP-specific site and decreased phosphorylation at the cyclic AMP-independent site.
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PMID:Basal phosphorylation of cyclic AMP-regulated phosphoproteins in intact S49 mouse lymphoma cells. 298 11


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