Disease relevance of Csnk2b

• Seryl/threonyl-protein kinases in cytosolic and particulate fractions from rat liver and AH-13, a rat ascites hepatoma, have been studied by chromatographing these fractions on DEAE-cellulose and assaying the eluates with casein, phosvitin, histone and protamine as substrates [1].
• Effects of phosvitin on the ecg changes induced under hypoxia in the rat [2].

High impact information on Csnk2b

• Both kinase preparations were essentially free of endogenous protein substrates and catalyzed the phosphorylation of exogenous substrates, such as casein and phosvitin, but not histone and protamine [3].
• The S6 kinase activated by insulin was highly specific for the ribosomal protein S6 when compared with various substrates, including casein, glycogen synthase, phosphorylase b, phosvitin, histone HIII-S, and histone HVIII-S [4].
• In addition, the activities of liver nucleolar protein kinases which were measured using casein or phosvitin as substrates were stimulated similarly by the administration of dexamethasone [5].
• This protein kinase phosphorylates in vitro ATP-citrate lyase, acetyl-CoA carboxylase, and glycogen synthase and does not phosphorylate phosphorylase, phosphorylase kinase, histone, phosvitin, and casein [6].
• The effect of diabetes on casein kinase 2 persisted after partial purification of the enzyme by glycerol-density-gradient centrifugation and affected also its activity on other protein substrates such as phosvitin, high-mobility-group protein 14 and glycogen synthase [7].

Biological context of Csnk2b

• Two protein kinases (I and II: EC 2.7.1.37) that show a high degree of substrate specificity for protamine rather than histones, phosvitin and casein were partly purified from rat epididymal tissue [8].
• The enzyme catalyzed the hydrolysis of adenosine 5'-triphosphate, adenosine 5'-diphosphate, thiamine pyrophosphate, inorganic pyrophosphate, and phosphoprotein such as casein and phosvitin, but not of several phosphomonoesters, except for p-nitrophenyl phosphate and o-phosphotyrosine [9].
• The inhibition profiles of dephosphorylation of phosvitin (50 micrograms/ml) showed IC50 values of 15 and 2 microM Al3+ at 1 and 48 hr incubation time, respectively [10].
• (b) Acetylation of both phosvitin and pronase phosphopeptides completely prevents their phosphorylation indicating that some lysine residues are strictly required for the phosvitin kinase reaction [11].

Anatomical context of Csnk2b

• Chromosomal phosvitin kinase strongly increased during the last days of fetal life; it strongly decreased just after birth and increased again for a short time, while the cytosol phosvitin kinase increased more significantly after birth [12].
• Rat dentin gamma-carboxyglutamate-containing protein of the osteocalcin type (Gla-protein), proteoglycan (PG), and phosphoprotein (PP-H), as well as phosvitin (PhV) and bovine serum albumin (BSA), were covalently linked to agarose beads [13].
• Reconstituted type I collagen as well as sheet collagen were crosslinked in the presence of alkaline phosphatase and egg-yolk phosvitin [14].
• Several phosphoprotein preparations (phosvitin, rat incisor and fetal calf molar dentin phosphoproteins) all inhibit apatite growth/replication from pre-existing crystal seeds in metastable solutions [15].
• Cyclic nucleotide-independent protein kinases that preferentially phosphorylated casein and phosvitin as substrate were detected in the nuclei of human and porcine thyroid tissues, and compared with those from rat liver [16].

Associations of Csnk2b with chemical compounds

• Casein kinase 2 (phosvitin kinase) and cyclic AMP-dependent protein kinase were unaffected [17].
• The circular dichroism spectrum of phosvitin was apparently altered by spermine, whereas no significant change was observed with casein [18].
• No cross-reactivity was found with phosvitin (a phosphoserine-rich phosphoprotein), rat serum albumin, bovine serum albumin, or collagen type IV [19].
• The kinase activities exhibit distinct substrate specificities and preference for either the basic substrates protamine sulfate and histones H1 and H3 (kinase activity PCV) or the acidic protein substrates casein (PC-II) and phosvitin (PC-III) [20].
• Exposure of fluorescein 5-isothiocyanate-labeled phosvitin to Al3+ resulted in: a) the failure of the protein to migrate into sodium dodecyl sulfate containing polyacrylamide gels and b) the decrease of the fluorescence emission of the bound fluorescein [10].

Other interactions of Csnk2b

• Phosphorylation of substrates currently used for protein kinase assays (histone H2B and phosvitin) was not stimulated [21].
• Phosvitin alone was found to prevent the hypoxia-induced T-wave changes (flattening or disappearance), which were also temporarily aggravated by injection of noradrenaline [2].
• Both enzymes were active towards casein, phosvitin, dephosphophosvitin, spermine-binding protein, and non-histone proteins in vitro [22].
• Dentin phosphoproteins are considerably more effective than phosvitin in retarding collagen self-assembly, with retardation times for these hard tissue extracellular matrix proteins being 25-30 times greater than control values [23].

Analytical, diagnostic and therapeutic context of Csnk2b

• Following FPLC/Superose 6 size exclusion chromatography of PvP1 and PvP2, single peaks of phosvitin phosphatase activities were eluted in the range of 160-220 kDa with acidic pH optima [24].
• Mineral formation, as monitored by scanning electron microscopy (SEM), was induced by all immobilized polyanions, including enzymatically dephosphorylated PP-H and PhV [13].
• Both cytosol and mitochondria of rat liver display protein kinase activity, cyclic AMP-independent, which is resolved by Sepharose 6B filtration and P-cellulose chromatography into multiple forms phosphorylating, besides endogenous mitochondrial membrane-bound proteins, also exogenous phosphoproteins such as casein and phosvitin [25].

References