PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 6297986

Decrease in uH2A (protein A24) of a mouse temperature-sensitive mutant.

Y Matsumoto·H Yasuda·T Marunouchi·M Yamada
View original source ↗Export metadata ↓

Abstract

ts85 cell is a temperature-sensitive mutant of cell cycle, and chromosomal protein uH2A of this mutant disappears at the non-permissive temperature. uH2A in nucleosomes is thought to be synthesized or degradated as follows. H2A + Ubiquitin in equilibrium uH2A. Up to date, the degradation of uH2A was shown to be catalyzed by uH2A lyase, however no enzymes (factors) concerning its synthesis have been elucidated. Here, we show that ATP is prerequisite for the synthesis of uH2A, and that the disappearance of uH2A at the non-permissive temperature may be due to a reduction in the rate of synthesis rather than an increase in the rate of its degradation.

Explore related subjects

2,4-DinitrophenolAdenosine TriphosphateAnimalsCell LineChromosomal Proteins, Non-HistoneDeoxyglucoseDinitrophenolsHistonesHot TemperatureKineticsMiceMutationNucleosomesUbiquitinsJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Y Matsumoto, H Yasuda, T Marunouchi, M Yamada. 1983-01-10. Decrease in uH2A (protein A24) of a mouse temperature-sensitive mutant.. https://doi.org/10.1016/0014-5793(83)80359-7

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1992

Cefaclor uptake by the proton-dependent dipeptide transport carrier of human intestinal Caco-2 cells and comparison to cephalexin uptake.

The human Caco-2 cell line spontaneously differentiates in culture to epithelial cells possessing intestinal enterocytic-like properties. These cells possess a proton-dependent dipeptide transport carrier that mediates the uptake of the cephalosporin antibiotic cephalexin (Dantzig, A.H. and Bergin, L. (1990) Biochim. Biophys. Acta 1027, 211-217). In the present study, the uptake of cefaclor was examined and found to be sodium-independent, proton-dependent, and energy-dependent. The initial rate of D-[3-phenyl-3H]cefaclor uptake was measured over a wide concentration range; uptake was mediated by a single saturable transport carrier with a Km of 7.6 mM and a Vmax of 7.6 nmol/min per mg protein and by a non-saturable component. Uptake was inhibited by dipeptides but not amino acids. The carrier showed a preference for the L-isomer. The effect of the presence of a 5-fold excess of other beta-lactam antibiotics was examined on the initial rates of 1 mM cefaclor and 1 mM cephalexin uptake. Uptake rates were inhibited by the orally absorbed antibiotics, cefadroxil, cefaclor, loracarbef, and cephradine and less so by the parenteral agents tested. The initial uptake rates of both D-[9-14C]cephalexin and D-[3-phenyl-3H]cefaclor were competitively inhibited by cephalexin, cefaclor, and loracarbef with Ki values of 9.2-13.2, 10.7-6.2, and 7.7-6.4 mM, respectively. Taken together, these data suggest that a single proton-dependent dipeptide transport carrier mediates the uptake of these orally absorbed antibiotics into Caco-2 cells, and provide further support for the use of Caco-2 cells as a cellular model for the study of the intestinal proton-dependent dipeptide transporter.

2,4-Dinitrophenol↗
PubMed1992

Uptake of polyamines by human endothelial cells. Characterization and lack of effect of agonists of endothelial function.

Uptake of polyamines by confluent monolayers of human umbilical-vein endothelial cells (HUVECs) was found to be time-, temperature- and concentration-dependent, energy-requiring, and saturable. Kinetic constants were putrescine Kt 3 +/- 1 microM, Vmax. 15 +/- 7 pmol/h per microgram of protein; spermidine, 0.7 +/- 0.2, 12 +/- 3; spermine, 1 +/- 0.7, 11 +/- 4. Putrescine uptake was inhibited by spermine or spermidine, whereas uptake of spermine or spermidine was not inhibited by 20 microM-putrescine. These data suggest the existence of two carriers, one shared by spermine and spermidine, and one capable of transporting all three polyamines. Pretreatment of HUVECs with thrombin (less than or equal to 10 units/ml; 1 h), bradykinin (less than or equal to 10 microM; 1 h), interleukin-1 (less than or equal to 100 units/ml; 2 h) or phorbol 12-myristate 13-acetate (less than or equal to 1.0 microM; 1 h), all known agonists of endothelial function, had no significant effect on polyamine uptake. These responses may be of importance in angiogenesis and wound healing, and could have pharmacological significance, for there is a growing interest in the use of polyamines or polyamine analogues as therapeutic agents.

2,4-Dinitrophenol↗
PubMed1992

Regulation of Na+/Ca2+ exchange in the rat pancreatic B cell.

Na+/Ca2+ exchange in the B cell was recently characterized by measuring intracellular-Na(+)-dependent 45Ca2+ uptake in isolated rat pancreatic islet cells. The aim of the present study was to investigate the regulation of this process. Extracellular pH (pHo) and intracellular pH (pHi) markedly affected Na+/Ca2+ exchange. A fall of 0.04 unit in pHi decreased the exchange by 45%, whereas a rise of 0.13 unit increased the uptake by 70%. Mitochondrial poisons (oligomycin, antimycin A and 2,4-dinitrophenol) inhibited reverse Na+/Ca2+ exchange by about 25-50%. The exchanger displayed a low Q10 (temperature coefficient), indicating that it is only indirectly dependent on metabolic energy. The phorbol ester phorbol 12-myristate 13-acetate did not affect Na+/Ca2+ exchange. Likewise, lowering the extracellular K+ concentration did not inhibit 45Ca2+ uptake. In conclusion, the pHi and the metabolic state of the cell may represent important modulatory signals by which insulin secretagogues such as glucose could regulate reverse Na+/Ca2+ exchange in the B cell. The process does not appear to co-transport K+ nor to be influenced by protein kinase C.

2,4-Dinitrophenol↗