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Lorenzo A Pinna - One of the best experts on this subject based on the ideXlab platform.
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Casein Kinases as potential therapeutic targets
Expert Opinion on Therapeutic Targets, 2016Co-Authors: Giorgio Cozza, Lorenzo A PinnaAbstract:Introduction: The conventional term ‘Casein kinase’ (CK) denotes three classes of Kinases – CK1, CK2 and Golgi-CK (G-CK)/Fam20C (family with sequence similarity 20, member C) – sharing the ability to phoshorylate Casein in vitro, but otherwise unrelated to each other. All CKs have been reported to be implicated in human diseases, and reviews individually dealing with the druggability of CK1 and CK2 are available. Our aim is to provide a comparative analysis of the three classes of CKs as therapeutic targets.Areas covered: CK2 is the CK for which implication in neoplasia is best documented, with the survival of cancer cells often relying on its overexpression. An ample variety of cell-permeable CK2 inhibitors have been developed, with a couple of these now in clinical trials. Isoform-specific CK1 inhibitors that are expected to play a beneficial role in oncology and neurodegeneration have been also developed. In contrast, the pathogenic potential of G-CK/Fam20C is caused by its loss of function. Activators...
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Casein kinase: the triple meaning of a misnomer
Biochemical Journal, 2014Co-Authors: Andrea Venerando, Maria Ruzzene, Lorenzo A PinnaAbstract:The term ‘Casein kinase’ has been widely used for decades to denote protein Kinases sharing the ability to readily phosphorylate Casein in vitro. These fall into three main classes: two of them, later renamed as protein Kinases CK1 (Casein kinase 1, also known as CKI) and CK2 (also known as CKII), are pleiotropic members of the kinome functionally unrelated to Casein, whereas G-CK, or genuine Casein kinase, responsible for the phosphorylation of Casein in the Golgi apparatus of the lactating mammary gland, has only been identified recently with Fam20C [family with sequence similarity 20C; also known as DMP-4 (dentin matrix protein-4)], a member of the four-jointed family of atypical protein Kinases, being responsible for the phosphorylation of many secreted proteins. In hindsight, therefore, the term ‘Casein kinase’ is misleading in every instance; in the case of CK1 and CK2, it is because Casein is not a physiological substrate, and in the case of G-CK/Fam20C/DMP-4, it is because Casein is just one out of a plethora of its targets, and a rather marginal one at that. Strikingly, Casein Kinases altogether, albeit representing a minimal proportion of the whole kinome, appear to be responsible for the generation of up to 40–50% of non-redundant phosphosites currently retrieved in human phosphopeptides database. In the present review, a short historical explanation will be provided accounting for the usage of the same misnomer to denote three unrelated classes of protein Kinases, together with an update of our current knowledge of these pleiotropic enzymes, sharing the same misnomer while playing very distinct biological roles.
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design and synthesis of two new peptide substrates for the specific and sensitive monitoring of Casein Kinases 1 and 2
Biochemical and Biophysical Research Communications, 1994Co-Authors: Oriano Marin, Flavio Meggio, Lorenzo A PinnaAbstract:Abstract The available information about the specificity determinants of Casein Kinases-1 and -2 (CK1 and CK2) has been utilized to obtain two new peptide substrates optimally suited for the specific monitoring of these two pleiotropic enzymes. The best substrate developed for CK1 is the inhibitor-2 derived peptide RRKDLHDDEEDEAMSITA which is superior in every respect to all the non phosphorylated CK1 peptide substrates used so far. Its Km is 172 μM and the Vmax is 6-fold higher than that of Casein. The dodecapeptide RRRADDSDDDDD, on the other hand, is totally refractory to CK1 while it is an excellent substrate for CK2, exhibiting, under basal conditions, a Km value of 19 μM and a Vmax higher than those obtained with all the routinely used substrates of CK2. Both the novel CK1 and CK2 peptide substrates are suited for the phosphocellulose paper assay.
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Casein Kinases an atypical class of ubiquitous and pleiotropic protein Kinases
1992Co-Authors: Lorenzo A Pinna, Flavio Meggio, Oriano Marin, John W Perich, Brigitte Boldyreff, Olafg IssingerAbstract:The term Casein kinase applies to a small group of Ser/Thr specific protein Kinases that by far prefer Casein over histones as in vitro substrates. While however genuine Casein Kinases specifically expressed in the lactating mammary gland are actually responsible for the biosynthetic phosphorylation of Casein fractions, two quite unrelated types of ubiquitous Casein Kinases, conventionally termed CK1 and CK2, are committed with the phosphorylation and regulation of a variety of protein targets involved in several cellular functions, with special reference to gene expression and signal transduction. CK2 is in particular a growth related protein kinase which, despite its heterotetrameric structure composed of two catalytic (α and/or α′) and two non catalytic (β) subunits, is spontaneously active and apparently lacks any acute control mechanism. Its canonical consensus sequence is Ser(Thr)-Xaa-Xaa-Glu(Asp, SerP, TyrP) but it can be surrogated in peptide substrates by atypical motif(s) generated by previously phosphorylated serines, notably (SerP)-SerP-Ser-SerP. CK2 specificity moreover can be deeply altered by polycationic effectors, like polylysine, and by the subunit composition of the enzyme, as disclosed by using its recombinant catalytic subunit (rα) and the reconstituted holoenzyme (rα2rβ2). It is proposed that such a multifarious and flexible specificity could provide CK2 with a sui generis mechanism of regulation.
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phosphorylation of src phosphopeptides by Casein Kinases 1 and 2 favourable effect of phosphotyrosine
Biochemical and Biophysical Research Communications, 1990Co-Authors: E A Kitas, Flavio Meggio, John W Perich, R M Valerio, R B Johns, Lorenzo A PinnaAbstract:The synthetic phosphotyrosyl tridecapeptide H-Arg-Leu-Ile-Glu-Asp-Asn-Glu-Tyr(P)-Thr-Ala-Arg-Gln-Gly-OH, reproducing a major phosphoacceptor site of protein tyrosine Kinases of the src-family, can be phosphorylated at Thr-9 by both Casein Kinases -1 and -2. Its shorter derivative H-Asn-Glu-Tyr(P)-Thr-Ala-OH is not affected by Casein kinase-1 while representing a substrate as good as the tridecapeptide for Casein kinase-2. The unphosphorylated analogue H-Asn-Glu-Tyr-Thr-Ala-OH, however, is a much poorer substrate, and no significant phosphorylation could be observed of its O-methyl ether derivative H-Asn-Glu-Tyr(Me)-Thr-Ala-OMe. These data on one side corroborate the concept that Casein kinase-1 recognizes residues located on the C-terminal edge of acidic stretches, providing, on the other, the evidence that phosphotyrosyl side chains can act as specificity determinants for Casein kinase-2.
S D Killilea - One of the best experts on this subject based on the ideXlab platform.
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hierarchical regulation by Casein Kinases i and ii of the activation of protein phosphatase 1i by glycogen synthase kinase 3 is ionic strength dependent
Archives of Biochemistry and Biophysics, 1993Co-Authors: S P Henry, S D KillileaAbstract:The roles of Casein Kinases I and II in the activation of protein phosphatase-1i (PP-1i) by glycogen synthase kinase-3 (GSK-3) were studied using enzyme preparations from porcine heart. PP-1i was activated by GSK-3 and the levels of activation achieved decreased by increasing the ionic strength (0-0.2 M KCl) in the incubation mixtures. At low ionic strength (no KCl added) Casein kinase II increased the rate of activation of PP-1i by GSK-3 and the activation proceeded to a slightly greater extent (110-120%) than that obtained by GSK-3 alone. In the presence of 0.14 M KCl only a partial activation of PP-1i by GSK-3 was observed, but when Casein kinase II was also added activation was restored to levels observed when PP-1i was activated by GSK-3 in the absence of salt. This effect was shown to be dependent on the concentration of Casein kinase II. These results would imply that at low ionic strength Casein kinase II and GSK-3 synergistically activate PP-1i as has been previously reported for the rabbit skeletal muscle enzyme (DePaoli-Roach, A. A., J. Biol. Chem. 259, 12144-12152, 1984), whereas, at physiological ionic strength, Casein kinase II action may be obligatory for GSK-3 activity. Similar results were obtained when Casein kinase I replaced Casein kinase II.
S P Henry - One of the best experts on this subject based on the ideXlab platform.
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hierarchical regulation by Casein Kinases i and ii of the activation of protein phosphatase 1i by glycogen synthase kinase 3 is ionic strength dependent
Archives of Biochemistry and Biophysics, 1993Co-Authors: S P Henry, S D KillileaAbstract:The roles of Casein Kinases I and II in the activation of protein phosphatase-1i (PP-1i) by glycogen synthase kinase-3 (GSK-3) were studied using enzyme preparations from porcine heart. PP-1i was activated by GSK-3 and the levels of activation achieved decreased by increasing the ionic strength (0-0.2 M KCl) in the incubation mixtures. At low ionic strength (no KCl added) Casein kinase II increased the rate of activation of PP-1i by GSK-3 and the activation proceeded to a slightly greater extent (110-120%) than that obtained by GSK-3 alone. In the presence of 0.14 M KCl only a partial activation of PP-1i by GSK-3 was observed, but when Casein kinase II was also added activation was restored to levels observed when PP-1i was activated by GSK-3 in the absence of salt. This effect was shown to be dependent on the concentration of Casein kinase II. These results would imply that at low ionic strength Casein kinase II and GSK-3 synergistically activate PP-1i as has been previously reported for the rabbit skeletal muscle enzyme (DePaoli-Roach, A. A., J. Biol. Chem. 259, 12144-12152, 1984), whereas, at physiological ionic strength, Casein kinase II action may be obligatory for GSK-3 activity. Similar results were obtained when Casein kinase I replaced Casein kinase II.
D L Nelson - One of the best experts on this subject based on the ideXlab platform.
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identification of a family of Casein Kinases in paramecium biochemical characterization and cellular localization
Biochemical Journal, 1993Co-Authors: C E Walczak, Richard A Anderson, D L NelsonAbstract:Protein phosphorylation is believed to play a role in the regulation of ciliary motility in the protozoan Paramecium tetraurelia. Five protein Kinases from Paramecium, activated by cyclic nucleotides or Ca2+, have been characterized previously. We report here the identification of a family of second-messenger-independent Casein Kinases in Paramecium. Casein kinase activity was enriched in the soluble fraction of cilia, but there was also significant activity tightly associated with axonemes. Three ciliary Casein kinase activities (soluble CKS1 and CKS2, and axonemal CKA) were separated by chromatography and characterized. The native forms of all three were monomeric, with molecular masses of 28-45 kDa as judged by in-gel kinase assays and sizing by gel filtration. CKS2 was inhibited by heparin, but CKA was unaffected and CKS1 was stimulated. All three activities preferred acidic substrates such as Casein and phosvitin, but they could be distinguished by their preference for other substrates. Antibodies against mammalian Casein kinase I recognized CKS1 and CKS2 in immunoblots (43 kDa), but did not stain CKA. The antibodies to Casein kinase I were used to probe other cellular fractions. A 65 kDa antigen (particulate Casein kinase, CKP) was enriched in particulate fractions of whole cells. This 65 kDa protein was found in isolated cell cortices, but was not present in the infraciliary lattice. This report represents the first biochemical identification of a Casein kinase I family in protozoa.
Renuzo Deana - One of the best experts on this subject based on the ideXlab platform.
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purification and characterization of two Casein Kinases from ejaculated bovine spermatozoa
Journal of Biochemistry, 1992Co-Authors: Maria Ruzzene, Arianna Donelladeana, Fabio Vianello, Renuzo DeanaAbstract:Two protein Kinases active on Casein and phosvitin were partially purified from the soluble fraction of ejaculated bovine spermatozoa. They were operationally termed Casein kinase A and B based on the order of their elution from a phosphocellulose column. CK-A showed an approximate molecular mass of 38 kDa, and it phosphorylated serine residues of Casein and phosvitin utilizing ATP as a phosphate donor (Km 19 microM). Enzyme activity was maximal in the presence of 10 mM MgCl2, whereas it decreased in the presence of spermine, polylysine, quercetin, and NaCl (20-250 mM). CK-B seemed to have a monomeric structure of about 41 kDa; it underwent autophosphorylation and cross-reacted with polyclonal antibodies raised against recombinant alpha, but not beta, subunit of human type 2 Casein kinase. It phosphorylated both serine and threonine residues of Casein and phosvitin, utilizing ATP (Km 12 microM) but not GTP as a phosphate donor. Threonine was more affected in the phosphorylated phosvitin than in the partially dephosphorylated substrate. CK-B was active toward the synthetic peptide Ser-(Glu)5 and calmodulin (in the latter case, in the presence of polylysine), and it was activated by spermine, polylysine, MgCl2 (30 mM), and NaCl (20-400 mM). The activity of the enzymes was not affected by cAMP, or the heat-stable inhibitor of the cAMP-dependent protein kinase, or calcium.