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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The influence of a specific histone kinase, phosphorylating lysin-rich histone H1, H2a, H2b on the physico-chemical properties of chromatin from hepatocytes of normal and hepatectomized guinea pigs has been investigated. A cytochemical method has been used which permits to obtain information about the physico-chemical properties of the chromatin in situ, i.e. without its isolation. This approach allows us to evaluate changes in chromatin properties in cell cultures as well as in the intact organism. It is found that the specific histone kinase changes the properties of chromatin in non-dividing cells bringing about an increase of acridine orange binding to the level characteristic for hepatocytes after partial hepatectomy. At the same time the chromatin properties in activated hepatocytes are not changed under the action of the histone kinase. It is concluded that the specific histone kinase, phosphorylating lysine-rich histones can play an important role in the course of chromatin activation in cells stimulated to proliferation.
Mol Biol (Mosk)
PMID:[Influence of histone kinase phosphorylating lysine-rich histones, on the physico-chemical properties of normal hepatocyte chromatin and after partial hepatectomy]. 22 34

Cyclic AMP-dependent protein kinase has been well established to be composed of catalytic and regulatory subunits, and cyclic AMP acts to dissociate these subunits to exhibit full enzymatic activity. In contrast, cyclic GMP-dependent protein kinase does not possess such a subunit structure and is activated by cyclic GMP simply in an allosteric manner. In addition to cyclic AMP-dependent and cyclic GMP-dependent protein kinases, another species of multifunctional protein kinase has been found in many mammalian tissues. This protein kinase is entirely independent of cyclic nucleotides and activated by lower concentrations of Ca2+ in the presence of a membrane-associated factor. This factor has been identified as phospholipids; in fact, phosphatidylinositol and phosphatidylserine are active in this role, whereas lecithin and sphingomyelin are unable to activate the enzyme. Thus, the three species of protein kinases mentioned above are activated in different manners. Nevertheless, these enzymes show very similar substrate specificities and phosphorylate the same specific seryl residues of histone fractions. In addition, all enzymes have abilities to activate and inactivate muscle phosphorylase kinase and glycogen synthetase, respectively, although the relative rates of reactions towards various substrates are markedly different. The Ca2+-dependent protein kinase seems to be associated with membranous components, whereas cyclic GMP-dependent protein kinase appears to be related to certain subcellular organella such as nucleus. Suggestive evidence is available implying that the cyclic AMP-, cyclic GMP- and Ca2+-activated three sets of protein kinase systems may play each specific physiological roles presumably owing to their own subcellular compartments.
Mol Cell Biochem 1979 Feb 09
PMID:Regulatory and functional compartment of three multifunctional protein kinase systems. 22 57

Histone kinase activity was purified from human polymorphonuclear leukocytes by ammonium sulphate precipitation of a 180 000 x g supernatant, followed by DEAE-cellulose chromatography and gelfiltration. On DEAE-cellulose cAMP dependent kinase activity eluted in two peaks, I and III, at 1.2 mmho and 6.5 mmho, respectively. Catalytic subunit (C) from both peaks had Mr 33 000, 3.0S. Regulatory subunit (R) from peak I and III both had Mr 33 000 upon gelfiltration, but sedimented at 2.8--3.0S and 3.0--3.2S, respectively. R2 and R4 subunits were identified. The R-C dimer from peak I and III sedimented at 4.8S and (4.8)--5.1S, respectively. The holoenzyme from peak I had Mr 165 000, 6.7S, which suggest a R2C2 structure, while that of peak III sedimented at 6.7S, but eluted at Mr 330 000 (2R2C2) by gelfiltration. The Kmapp for peak I and III enzymes were, respectively: histone IIA 0.5 mg/ml (both forms), ATP 18 microM and 23 microM, and cAMP 5 X 10(-8) M and 6.3 x 10(-8) M. Both enzymes had pH optimum 6.7--6.9 and were equally sensitive to Ca2+, temperature and protein kinase inhibitor. The substrate specificity was histone VS greater than histone IIA = histone VIS greater than casein greater than phosvitin. Peak I enzyme, but not peak III enzyme, was dissociated by histone and high ionic strength and reassociation of R and C subunits were facilitated by ATP-Mg. It is concluded that peak I and III enzymes represent type I and II cAMP dependent protein kinases, respectively. Type I comprises 20--30% of cAMP dependent protein kinase activity and is absent from the 180 000 x g supernatant of gently disrupted cells. Purified catalytic subunit had Kmapp (ATP) 20 microM with rabbit muscle glycogen synthease I as substrates. Synthase I from rabbit muscle and human leukocytes were phosphorylated by catalytic subunit to synthase D (ratio of independence less than 0.07). cAMP independent histone kinase activity eluted in one peak (Peak II) at3 mmho. The enzymatic activity sedimented at 3.4S and eluted from gelfiltration with Mr 78 000. Kmapp for ATP was 78 microM and for histone IIA 0.5 mg/ml. The enzyme was sensitive to temperature, but less sensitive than cAMP dependent protein kinase to Ca2+, and insensitive to protein kinase inhibitor. The substrate specificity was histone IIA greater than histone VS = histone VIS, while casein and phosvitin were poor substrates. Glycogen synthase I was not phosphorylated. The cAMP independent histone kinase activity comprised 15% of the total histone kinase activity in a crude homogenate of leukocytes. Its physiological substrate is unknown.
Mol Cell Biochem 1979 Jul 15
PMID:Purification and properies of cAMP dependent and independent histone kinases from human leukocytes. 22 66

The chromatin core particle DNA conformation deduced in broad outline by Finch et al. [Finch, J. T., Lutter, L. C., Rhodes, D., Brown, R. S., Rushton, B., Levitt, M. & Klug, A. (1977) Nature 269, 29-36] can be described in detail using other available experimental results. Histone binding sites compatible with the pattern of pancreatic DNase I digestion (Simpson, R. T. & Whitlock, J. P., Jr. (1976) Cell 9, 347-353; Noll, M. (1977) J. Mol. Biol. 116, 49-71; Lutter, L. C. (1977) J. Mol. Biol. 117, 53-69] lend to core particle DNA pseudosymmetry characteristic of molecular point group D(3). DNA symmetry and pseudosymmetry, in turn, imply equivalence and quasi-equivalence properties of the histone packing arrangement that support the following deductions: (i) One and only one alpha(2)beta(2) histone tetramer, presumably (H3)(2)(H4)(2), can serve as a stable subassembly within the histone octamer. (ii) There is a unique, strand-specific way to assign DNA binding domains to the arginine-rich histones (H3 and H4). (iii) Histones H3 and H4 alone should suffice to impose a supercoiled structure on DNA, as is observed experimentally, because only the tetramer can mimic a screw dislocation and thereby complement the screw symmetry of the DNA supercoil. (iv) The two slightly lysine-rich histones H2A and H2B are probably responsible, each in a different way, for dividing the eukaryotic chromatin fiber into discrete subunits. (v) The proposed arrangement of four distinct proteins appears to be a minimum formal requirement for making nucleosomes; that is, for introducing regularly spaced supercoiled DNA folds without also allowing formation of an indefinitely long (and genetically inert) DNA superhelix.
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PMID:Histone packing in the nucleosome core particle of chromatin. 27 80

The state of the major and the minor DNA grooves in purified mono- and oligonucleosomes and in the complexes of DNA with different histones have been studied by means of methylation of DNA with dimethyl sulphate. In nucleosomes histones shielded major groove by 18--20%. This result agrees well with our previous data obtained with chromatin, nuclei and whole cells. Each of the purified histones H2a, H2b, H3 and H4 as well as N-terminal peptides of H4 histone cause relative shielding of the DNA major groove by 15--18% like whole histone does. H1 histone protects neither DNA grooves from methylation. Our results suggest that histones are buried partly in the major groove of DNA in chromatin and purified nucleosomes. The arrangement of histones in the major groove does not depend probably on their specific organization in nucleosomes.
Mol Biol (Mosk)
PMID:[State of DNA slots in mono- and oligonucleosomes and in DNA complexes with individual histones]. 34 61

Yeast chromatin, isolated by a rapid procedure contains in addition to histones H2A, H2B, H3 and H4 a fifth major basic protein. This fifth polypeptide is not an intrinsic component of the nucleosome structure. It has properties of both histone and nonhistone proteins and might represent an early form of histone H1 and of high mobility group nonhistone proteins of higher eukaryotes. Electron microscopic visualization of isolated yeast nucleosomes substaniates further the similarity of the chromatin structudre of this unicellular eukaryote to that of higher eukaryotes.
Mol Gen Genet 1978 May 31
PMID:Yeast chromatin: search for histone H1. 35 18

Fractionation of acid-soluble proteins from yeast Saccharomyces cerevisiae chromatin by gel electrophoresis suggested the existence of four histonestone fractions--H2a, H2b, H3, H4 and histone H1-like protein. The latter was isolated according to the second method of Johns and extracted with 5% HClO4. Amino acid analysis of the histone H1-like protein showed a moderately high content of basic amino acids, but a much lower ratio of lysine: arginine (approximately 3) than that of the hisone H1 from higher eukaryotes. In addition to histone H1-like protein a protein X was also extracted with 5% HC1O4. The sequence of the electrophoretic mobilities of histone fractions from yeast coincides with those of histone fractions from plants--H4 greater than H3 greater than H2a greater than H2b greater than H1.
Mol Biol (Mosk)
PMID:[Electrophoretic study of the acid soluble proteins of Saccharomyces cerevisiae yeast chromatin]. 35 66

Splitting of DNA in rat thymus nuclei by Serratia marcescens endonuclease has been studied. DNA fragments were analyzed by gel electrophoresis. Obtained data indicate that the internucleosomal DNA interacts with histones octamer and is cut by endonuclease to fragments multiple of 10 nucleotides. Limits digestion of nuclei with Serratia endonuclease (up to 50% of DNA acid solubility) leaves in a nondegraded form the chromatin fragments including DNA pieces up to 1000 bases in size-resistant DNA. Partly, the resistant DNA has properties of single-stranded molecules. These data are interpreted so that Serratia endonuclease is able to hydrolyse with some preference one of the DNA strands in chromatin. It can be considered as an evidence of different modes of interaction of the histone core with the two DNA strands.
Mol Biol (Mosk)
PMID:[Arrangement in chromatin of DNA sites accessible to Serratia marcescens endonuclease]. 36 99

RNA synthesis, correlation of various histones and acetylation and phosphorylation of the chromatin proteins were studied in the rat heart during monthly hypothyroidism. It was shown that [3H]uridine incorporation into heart RNA decreases considerably at hypothyrosis. The alteration in relative amounts of the histone H4 subfractions, which does not depend on the method of hypothyrosis reproduction (inhibition of thyroid function by 1-methyl-2-mercaptoimidazole, thyroidectomy) was detected by the method of analytical electrophoresis in 15% polyacrylamide gels containing 3.125 M urea and 0.9 N acetic acid. Increased incorporation of [32P]phosphate into histone fraction H2b and total fraction of acidic chromatin proteins was observed in vivo. Increased incorporation of labeled acetate into the total histone fraction and reduced incorporation into acidic nuclear proteins were obtained. It was shown that the increased incorporation of acetate into the total histone fraction was due to the increased acetylation of histones H3, H2b, H4 and acid-soluble chromatin proteins characteristic of tissues with a low level of replication. It is assumed that the observed changes of nuclear proteins reflect the process of chromatin reorganization caused by a prolonged deficiency of thyroid hormones.
Mol Biol (Mosk)
PMID:[RNA synthesis and modifications of heart nuclear proteins during thyroid hormone deficiency]. 46 Jan 95

Contrary to some recent reports DNA synthesis in isolated HeLa cell nuclei was not stimulated by the addition of low amounts of histones neither in the presence nor in the absence of cytosol. The individual histone fractions H1, H2A, H2B and H3 also failed to stimulated DNA synthesis.
Mol Biol Rep 1979 Aug 31
PMID:No stimulatory effect of added histones on DNA synthesis in isolated HeLa cell nuclei. 49 63


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