Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In cell homogenates of Dictyostelium discoideum, strain AX-2, four major soluble protein kinases (ATP:protein phosphotransferase, EC 2.7.1.37) and one membrane-associated protein kinase activity were identified. The enzymes showed high affinity for casein. One of the enzymes was purified by affinity chromatography on casein-coated Sepharose. The soluble high molecular weight enzymes phosphorylated histones, whereas the low molecular weight enzymes did not. The same protein kinase species were present in vegetative and aggregation-competent cells. Their specific activity, however, changed during the development to aggregation competence. None of the enzymes was stimulated by cyclic AMP or cyclic GMP, regardless of their origin from vegetative or aggregation-competent cells.
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PMID:Protein kinases of Dictyostelium discoideum, strain AX-2. 22 Oct 22

cDNA clones encoding the regulatory subunit of the cAMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) from Dictyostelium discoideum were isolated by immunoscreening of a cDNA library constructed in the expression vector lambda gt11. High-affinity cAMP-binding activity was detected in extracts from bacteria lysogenized with these clones. Nucleotide sequence analysis of three overlapping clones allowed the determination of a 1195-base-pair cDNA sequence coding for the entire regulatory subunit and containing nontranslated 5' and 3' sequences. The open reading frame codes for a protein of 327 amino acids, with molecular weight 36,794. The regulatory subunit from Dictyostelium shares a high degree of homology with its mammalian counterparts, but is lacking the NH2-terminal domain required for the association of regulatory subunits into dimers in other eukaryotes. On the basis of the comparison of the regulatory subunits from Dictyostelium, yeast, and bovine tissues, a model for the evolution of these proteins is proposed.
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PMID:Cloning and cDNA sequence of the regulatory subunit of cAMP-dependent protein kinase from Dictyostelium discoideum. 346 59

Cyclic AMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) in Dictyostelium discoideum was shown to be developmentally controlled. No activity was measured in vegetative cells, but activity increased rapidly during differentiation. A simple procedure for the isolation of the catalytic subunit of the kinase from aggregating cells is presented. The cyclic AMP-dependent holoenzyme could be reconstituted by adding purified D. discoideum cyclic AMP-binding protein. Molecular weight, kinetic parameters, pH dependence and affinity for cyclic AMP were determined for the enzyme. Most properties are similar to those of cyclic AMP-dependent kinase from mammalian cells.
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PMID:Isolation and properties of cyclic AMP-dependent protein kinase from Dictyostelium discoideum. 631 30

In this study, we examined the activation mechanism of Dictyostelium myosin light chain kinase A (MLCK-A) using constitutively active Ca2+/calmodulin-dependent protein kinase kinase as a surrogate MLCK-A kinase. MLCK-A was phosphorylated at Thr166 by constitutively active Ca2+/calmodulin-dependent protein kinase kinase, resulting in an approximately 140-fold increase in catalytic activity, using intact Dictyostelium myosin II. Recombinant Dictyostelium myosin II regulatory light chain and Kemptamide were also readily phosphorylated by activated MLCK-A. Mass spectrometry analysis revealed that MLCK-A expressed by Escherichia coli was autophosphorylated at Thr289 and that, subsequent to Thr166 phosphorylation, MLCK-A also underwent a slow rate of autophosphorylation at multiple Ser residues. Using site-directed mutagenesis, we show that autophosphorylation at Thr289 is required for efficient phosphorylation and activation by an upstream kinase. By performing enzyme kinetics analysis on a series of MLCK-A truncation mutants, we found that residues 283-288 function as an autoinhibitory domain and that autoinhibition is fully relieved by Thr166 phosphorylation. Simple removal of this region resulted in a significant increase in the kcat of MLCK-A; however, it did not generate maximum enzymatic activity. Together with the results of our kinetic analysis of the enzymes, these findings demonstrate that Thr166 phosphorylation of MLCK-A by an upstream kinase subsequent to autophosphorylation at Thr289 results in generation of maximum MLCK-A activity through both release of an autoinhibitory domain from its catalytic core and a further increase (15-19-fold) in the kcat of the enzyme.
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PMID:Regulatory mechanism of Dictyostelium myosin light chain kinase A. 1457 Aug 71