Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.11 (AMPK)
 12,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An unusual monomeric cGMP-dependent protein kinase, enriched in cilia, was isolated from Paramecium cilia and whole cells. Cilia and whole cell extracts had relatively high ratios of cGMP-dependent to cAMP-dependent protein kinase activity (1:2). The calculated molecular weight of the native enzyme was 88,000. The enzyme was identified on sodium dodecyl sulfate-polyacrylamide gels as a 77,000 molecular weight band based on copurification of this protein with enzyme activity, 8-N3-[32P]cAMP labeling, and autophosphorylation. Based on the size of the native enzyme, it was concluded that the kinase is a monomer with cGMP-binding and catalytic activities on the same polypeptide. Dimer-sized cGMP-dependent protein kinase, like that of the well characterized mammalian enzyme, was never seen, despite stringent efforts to control proteolysis. The structure of the Paramecium cGMP-dependent protein kinase supports a model in which the dimeric vertebrate form of the enzyme evolved from an early monomeric form. The catalytic properties of the Paramecium enzyme differed in several respects from those of the mammalian enzyme: it could use GTP or ATP as the phosphoryl donor, it did not phosphorylate Kemptide effectively, and it had poor histone kinase activity with high Mg2+ concentrations. Quercertin, 5'-guanylyl imidodiphosphate, indomethacin, and the isoquinolinesulfonamide drug H7 inhibited Paramecium cGMP-dependent protein kinase activity. The enzyme had fast and slow binding sites (with kd values of 5-10 x 10(-3)s-1 and 0.44 x 10(-3)s-1) and showed an order of preference for cyclic nucleotides and cyclic nucleotide analogs similar to that of the mammalian enzyme.
 ...
PMID:A novel cGMP-dependent protein kinase from Paramecium. 318 84

We have used mammalian probes to clone genes encoding the catalytic (C) and type I regulatory (RI) components of the cAMP-dependent protein kinase in Drosophila. Both Drosophila gene products are very similar in amino acid sequence (RI, 71%; C, 82%) to their respective mammalian counterparts, implying homologous activity. A single Drosophila type I regulatory subunit gene is the source of at least three distinct transcripts originating from different promoters and spliced to a common body that would encode a full-length analog and two amino-terminally truncated variants of the mammalian RI protein. The RI locus also includes two intronic genes of unknown function. A single highly conserved catalytic subunit gene (DC0) was found that codes for a single polypeptide. It was used to isolate 11 further more distantly related apparent protein kinase genes. Two of these genes (DC1 and DC2) are sufficiently similar to DC0 in sequence (45% and 49% amino acid identity, respectively) that they could conceivably encode products of overlapping function. Two further genes are very similar in sequence to bovine cGMP-dependent protein kinase. The remaining putative gene products include amino acid sequence motifs characteristic of serine-threonine protein kinases but cannot, from the available data, be defined as homologous to specific protein kinases of other organisms.
 ...
PMID:Isolation and characterization of Drosophila cAMP-dependent protein kinase genes. 321 11

It has been shown that cAMP-dependent phosphorylation of a soluble sperm protein is important for the initiation of flagellar motion. The suggestion has been made that this motility initiation protein, named axokinin, is the major 56,000-dalton phosphoprotein present in both dog sperm and in other cells containing axokinin-like activity. Since the regulatory subunit of a type II cAMP-dependent protein kinase is a ubiquitous cAMP-dependent phosphoprotein of similar subunit molecular weight as reported for axokinin, we have addressed the question of how many soluble 56,000-dalton cAMP-dependent phosphoproteins are present in mammalian sperm. We report that in bovine sperm cytosol, the ratio of the type I to type II cAMP-dependent protein kinase is approximately 1:1. The type II regulatory subunit is related to the non-neural form of the enzyme and undergoes a phosphorylation-dependent electrophoretic mobility shift. The apparent subunit molecular weights of the phospho and dephospho forms are 56,000 and 54,000 daltons, respectively. When bovine sperm cytosol or detergent extracts are phosphorylated in the presence of catalytic subunits, two major proteins are phosphorylated and have subunit molecular weights of 56,000 and 40,000 daltons. If, however, the type II regulatory subunit (RII) is quantitatively removed from these extracts using either immobilized cAMP or an anti-RII monoclonal affinity column, the ability to phosphorylate the 56,000- but not 40,000-dalton polypeptide is lost. These data suggest that the major 56,000 dalton cAMP-dependent phosphoprotein present in bovine sperm is the regulatory subunit of a type II cAMP-dependent protein kinase and not the motility initiator protein, axokinin.
 ...
PMID:Major 56,000-dalton, soluble phosphoprotein present in bovine sperm is the regulatory subunit of a type II cAMP-dependent protein kinase. 339 99

Purified RNA polymerase II from chicken leukemia cells was found to be an effective substrate for protein kinase C but not cAMP-dependent protein kinase. Protein kinase C catalyzed the incorporation of 1-2 mol of phosphate per mol of polymerase II and the reaction was totally calcium and lipid dependent. Electrophoresis studies revealed a time-dependent increase of phosphate incorporation into RNA polymerase II subunits of 220 KDa, 180 KDa and 150 KDa, with a preferential phosphorylation of the 180 KDa polypeptide. The phosphorylated enzyme has a preference for using single-stranded DNA as the template for transcription, including transcription of the single-stranded myb oncogene sequence. Phosphoamino acid analysis indicated that both serine and threonine residues were phosphorylated at equal amounts. Phosphorylation by protein kinase C increased the affinity of substrate-polymerase binding and the initial rate of RNA synthesis, suggesting a mechanism by which gene expression can be activated by protein kinase C.
 ...
PMID:Protein kinase C phosphorylates leukemia RNA polymerase II. 347 67

The purified type I regulatory subunit of cAMP-dependent protein kinase is a dimeric protein, and the two protomers of the dimer are linked by two interchain disulfide bonds. The disulfide linkages that join these two polypeptide chains have been identified in order to provide a structural basis for the orientation of the two chains in the asymmetric dimer. Disulfide bonds were found to exist exclusively between Cys-16 and Cys-37, and this assignment, thus, establishes a general antiparallel alignment of the two chains. Two other homologous proteins, the type II regulatory subunit and the cGMP-dependent protein kinase also are dimeric proteins. In all three proteins, a relatively small, nonhomologous, amino-terminal segment of the polypeptide chain is essential for maintaining the dimeric aggregation state.
 ...
PMID:Antiparallel alignment of the two protomers of the regulatory subunit dimer of cAMP-dependent protein kinase I. 366 18

We have examined the phosphorylation of the chicken progesterone receptor in tissue slices and in vitro. The receptor is phosphorylated in tissue slices and this phosphorylation is stimulated by progesterone. As others have reported, partially purified receptor preparations contain a kinase activity which phosphorylates histones and receptor. We have shown that this activity can be separated from the receptor. The receptor is a substrate for several kinases, including the catalytic subunit of the cAMP-dependent protein kinase and PPdPK, a polypeptide-dependent protein kinase. Phosphorylation by the cAMP-dependent protein kinase results in an apparent increase in the molecular weight of the receptor when the receptor is analyzed by SDS-PAGE. These results are consistent with apparent changes in molecular weight observed for rabbit and human progesterone receptor upon treatment of tissue or cells with hormone.
 ...
PMID:Phosphorylation of the chicken progesterone receptor. 369 83

cAMP is an important effector of the development of Dictyostelium discoideum amoebae and could exert its effects on gene expression through the cytosolic cAMP-dependent protein kinase (cAK). Antibodies, specific for the regulatory subunit (R) of the cAK, were used to investigate the developmental regulation of the corresponding mRNA (R-mRNA) by in vitro translation and immunoprecipitation. Under such conditions, a single polypeptide of the same mol. wt. as R (42 kd) is detected, showing that the protein is not synthesized as a large precursor. The level of the R-mRNA, which is low in vegetative cells, increases 10- to 20-fold during the first hours of development. Its expression is stimulated by the treatment of AX3 cells with cAMP either added to a concentration of 1 mM or given as 0.1 microM pulses every 5 min, whereas such treatments have little or no effect in cells of strain AX2. The R-mRNA remains highly expressed (0.01-0.03% of translatable mRNA) throughout post-aggregative development; it is not affected by mechanical disaggregation of the multicellular organism. The parallel developmental time courses of the translatable R-mRNA and the R protein produced in vivo suggest that the expression of this polypeptide is regulated at the level of mRNA synthesis.
 ...
PMID:Detection and developmental regulation of the mRNA for the regulatory subunit of the cAMP-dependent protein kinase of D. discoideum by cell-free translation. 370 16

The amino acid sequence of rabbit skeletal muscle heat-stable inhibitor of the cAMP-dependent protein kinase has been determined by microsequencing techniques. Proof of the structure involved a series of nonoverlapping tryptic fragments for primary identification of 86% of the amino acids. Complementary fragments generated by cleavage with chymotrypsin, Staphylococcus aureus V8 proteinase, and mast cell proteinase II contributed to proof of the structure. The inhibitor is a single polypeptide chain of 75 residues and has a molecular weight of 7829. It lacks tryptophan, proline, and sulfur-containing amino acids. The amino terminus of the inhibitor is blocked by an unidentified group. The amino-terminal region of the molecule contains the kinase inhibitory domain, and synthetic peptides based on the sequence of residues 11-30 are potent competitive inhibitors of the cAMP-dependent protein kinase [Scott, J. D., Fischer, E. H., Demaille, J. G. & Krebs, E. G. (1985) Proc. Natl. Acad. Sci. USA 82, 4379-4383]. Residues 14-22 show considerable homology to the "hinge-regions" of the regulatory subunits of the cAMP-dependent protein kinase. The remainder of the molecule shows no similarity to the known amino acid sequence of any protein.
 ...
PMID:Amino acid sequence of the heat-stable inhibitor of the cAMP-dependent protein kinase from rabbit skeletal muscle. 389 70

Polyamine-dependent protein kinase (P kinase) in nuclear and cytosol fraction of pig epidermal cells were extracted. Two different protein kinases were purified from nuclei. One was cAMP-dependent protein kinase (A kinase) and another was P kinase. P kinase phosphorylated acidic non-histone protein only, while A kinase phosphorylated both exogenous histone and non-histone proteins. Among polypeptides phosphorylated by P kinase, a 180 kilodalton (K) polypeptide seemed to be a specific substrate for P kinase. In cytosol, the fraction containing P kinase exhibited multiple polypeptide bands on SDS -PAGE, including four major polypeptide bands and several minor polypeptide bands. One of minor polypeptide bands (80 K) was phosphorylated by P kinase. Authentic ornithine decarboxylase (ODC) added exogenously was also phosphorylated by P kinase. A 80 K polypeptide of ODC was comigrated with the polypeptide phosphorylated by P kinase on SDS -PAGE. Kinetic study revealed that the ODC activity decreased as ODC was phosphorylated.
 ...
PMID:[Studies on polyamine-dependent protein kinase in pig epidermal cells]. 398 33

Plasma membranes from bovine epididymal spermatozoa possess both cAMP-independent and cAMP-dependent protein kinase activity. With the synthetic peptide, Leu-Arg-Arg-Ala-Ser-Leu-Gly as substrate, the basal activity of the membrane-associated protein kinase(s) was 0.1 nmol phosphate incorporated X min X mg protein. In the presence of 5 microM cAMP, the apparent activity was increased about twofold. The addition of Nonidet P-40 (0.05%) to the assay mixture increased protein kinase activity to 0.4 and 4.0 nmol phosphate incorporated X min X mg protein in the absence or presence of 5 microM cAMP, respectively. Both isozymes of the cAMP-dependent protein kinase were detected in detergent-solubilized membranes but 95% of the activity appeared as a Type II form based on DEAE-Sephacel chromatography. Several polypeptide components of the plasma membrane served as substrates for membrane-associated cAMP-dependent protein kinases, in vitro. In the absence of detergent, two cAMP-dependent phosphoproteins of 41,000 Mr and 60,000 Mr were detected by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. When 0.05% Nonidet P-40 was included in the assay mixture, a cAMP-dependent phosphoprotein of 43,000 Mr appeared. Two-dimensional polyacrylamide gel electrophoresis of membranes phosphorylated in the presence of 5 microM and 0.05% Nonidet P-40 revealed phosphoproteins of the following molecular weights/isoelectric points: 56,000/6.7, 56,000/6.9, 51,000/6.2, 42,000/5.9, 42,000/6.0, 38,000/6.1, 38,000/6.4, 14,000/7.2, 12,000/7.4 and a train of five polypeptides appearing at 14,000/5.4-6.0.
 ...
PMID:Protein phosphorylation of plasma membranes from bovine epididymal spermatozoa. 608 45


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>