Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Members of the Rh/T2/S-glycoprotein family of ribonuclease(RNase)-encoding genes have been found predominantly in fungi, plants and bacteria, where they have been implicated in functions as diverse as the phosphate-starvation response and self-incompatibility. We report the isolation and sequence of DmRNase-66B, the first member of this family to be found in an insect genome. This gene was identified by the analysis of a cDNA clone derived from cytological region 66B1-2 of the genome of Drosophila melanogaster. In a search of sequence databases for homologs of this gene, two animal viral proteins, gp53 of the bovine viral diarrhea virus (BVDV) and gp44/48 of the hog cholera virus (HCV), were also found to exhibit the characteristic features of this class of RNases. In all cases, the proteins contain two conserved pentameric amino-acid regions that have been shown to lie in the active site of these RNases. A series of Cys residues are also conserved in all members of this gene family. The discovery of members of this family of genes in an insect genome indicates that these RNases are widely conserved and play important roles in the animal, as well as the plant and prokaryotic kingdoms.
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PMID:The Drosophila melanogaster genome contains a member of the Rh/T2/S-glycoprotein family of ribonuclease-encoding genes. 760 42

The secretion pathway of Saccharomyces cerevisiae was challenged by constitutively overexpressing plasmid-encoded acid phosphatase, a secreted endogenous glycoprotein. A 2-microns-based multicopy plasmid carrying the coding sequence of acid phosphatase under the control of a truncated variant of the strong constitutive glyceraldehyde-3-phosphate dehydrogenase promoter was used for expression. Selection for the promoterless dLEU2 marker leads to a growth arrest. This is not per se due to leucine starvation, but due to intracellular accumulation of highly glycosylated enzymatically active acid phosphatase. Immunofluorescence and cytological analysis indicate that intracellular accumulation of acid phosphatase occurs in a subpopulation of cells. By Ludox-AM density centrifugation, these cells can be enriched on the basis of their higher density. The dense accumulating cells have a higher average plasmid copy number and produce more acid phosphatase than non-accumulating cells of low density. These cells are defective in directed secretion and bud formation, therefore can no longer grow and show dramatic changes in cell morphology. We suggest that the secretion pathway in these cells is overloaded with the high level of acid phosphatase leading to a shutdown in vectorial secretion, subsequently to a standstill in growth and to the intracellular accumulation of further expressed acid phosphatase. We have indications that accumulation of acid phosphatase occurs in the late Golgi, suggesting a limitation of the overall secretion at this stage.
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PMID:High-level expression of endogenous acid phosphatase inhibits growth and vectorial secretion in Saccharomyces cerevisiae. 775 60

Aeromonas hydrophila, a ubiquitous inhabitant of aquatic environments, commonly expresses several cell-surface properties that may contribute to virulence. Since many aquatic microorganisms in hostile environments can withstand starvation conditions for long periods, we examined the effect of storage under nutrient-poor conditions on the expression of cell-surface properties of this pathogen. Phenotypes studied were: (1) cell-surface hydrophobicity and charge, and (2) the ability to bind connective-tissue proteins and lactoferrin. Our results suggest that the response of A. hydrophila to nutrient-poor conditions is regimen specific. Generally, A. hydrophila cells became more hydrophobic and significantly increased their ability to bind the iron-binding glycoprotein lactoferrin when the bacterium was stored under nutrient-poor conditions; however, under these conditions, the cells seemed to lose their ability to bind connective-tissue proteins.
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PMID:Cell-surface properties of the food- and water-borne pathogen Aeromonas hydrophila when stored in buffered saline solutions. 779 3

Colonization of the oral cavity by Candida albicans involves adherence of yeast cells to oral surfaces. An assay was developed to measure the attachment of C. albicans cells, metabolically labelled with [35S]methionine, to saliva-coated hydroxylapatite (SHA) beads--a model for the tooth surface. Using this assay approximately 1.26 x 10(6) C. albicans cells (50.5% of input cells) attached to the SHA beads (12 mg). Different strains of C. albicans adhered to varying degrees to SHA beads, but in general adherence was promoted by growth of cells at 28 degrees C and by starvation of cells for glucose. Proteins in human whole, or parotid, saliva samples were fractionated by gel filtration (Sephacryl S-200 column) and fractions were adsorbed to hydroxylapatite beads. Fractions that contained proline-rich proteins or statherin promoted attachment of C. albicans ATCC 10261 cells. Neuraminidase treatment of SHA beads, but not of cells, significantly increased yeast cell binding to the SHA beads. Neuraminidase activity in the oral cavity may unmask glycoprotein receptors involved in the adhesion of C. albicans to saliva-coated surfaces.
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PMID:Adherence of Candida albicans to human salivary components adsorbed to hydroxylapatite. 789 15

Confluent monolayer cultures of the bovine kidney cell line NBL-1 were starved of amino acids in the presence of tracer concentrations of [35S]-methionine. Fluorographs of SDS-polyacrylamide gel separated membrane proteins revealed increased labelling of at least two proteins in starved cells relative to those in cells grown in complete medium. The patterns of Coomassie blue stained proteins from Concanavalin A-purified fractions of cells grown under fed and amino acid-starved conditions were similar but fluorography indicated the presence of one major labelled glycoprotein with a molecular weight of 62 kD in starved cells which was not present in fed cells. N-terminal amino acid analysis of the first 15 amino acids of the 62 kD protein and a protein of 60 kD found in control cells identified both proteins as calreticulin. N-terminal amino acid sequence analysis of a second amino acid starvation-up-regulated protein identified it as glucose-regulated protein GRP78. The amino acid sequences of calreticulin, GRP78 and two transport proteins known to be induced in amino acid starvation, have a common motif near the C-terminal end of the molecule. It is suggested that calreticulin is a member of a novel class of stress proteins induced by amino acid starvation.
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PMID:Calreticulin--a stress protein induced in the renal epithelial cell line NBL-1 by amino acid deprivation. 795 7

The multicellular alga Volvox is an attractive model for the study of developmental processes. With the recent report of successful transformation, regulated promoters as well as reporter genes working in this organism are now required. The Volvox genes encoding arylsulfatase and the extracellular glycoprotein ISG are strictly regulated. The former is transcribed only under conditions of sulfur starvation, whereas the latter operates under extreme developmental control--i.e., it is transcribed for only a few minutes in Volvox embryos at the stage of embryonic inversion. The gene encoding the sexual pheromone of Volvox carteri was placed under the control of the arylsulfatase promoter. In response to sulfur deprivation, V. carteri transformed by this construct synthesized and secreted biologically active pheromone. In addition, the gene encoding Volvox arylsulfatase was placed under the control of the ISG promoter. Transformed algae synthesized arylsulfatase mRNA only during embryonic inversion. These experiments demonstrate the usefulness of both the arylsulfatase and the sexual pheromone reporter genes. In addition, the highly regulated arylsulfatase promoter allows the construction of inducible expression vectors for cloned genes.
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PMID:Reporter genes and highly regulated promoters as tools for transformation experiments in Volvox carteri. 797 2

Anoxia, glucose starvation, calcium ionophore A23187, EDTA, glucosamine, and several other conditions that adversely affect the function of the endoplasmic reticulum (ER) induce the synthesis of the glucose-regulated class of stress proteins (GRPs). The primary GRPs induced by these stresses migrate at 78 and 94 kDa (GRP78 and GRP94). In addition, another protein of approximately 150-170 kDa (GRP170) has been previously observed and is coordinately induced with GRP78 and GRP94. To characterize this novel stress protein, we have prepared an antisera against purified GRP170. Immunofluorescence, Endoglycosidase H sensitivity, and protease resistance of this protein in microsomes indicates that GRP170 is an ER lumenal glycoprotein retained in a pre-Golgi compartment. Immunoprecipitation of GRP170 with our antibody coprecipitates the GRP78 (also referred to as the B cell immunoglobulin-binding protein) and GRP94 members of this stress protein family in Chinese hamster ovary cells under stress conditions. ATP depletion, by immunoprecipitation in the presence of apyrase, does not affect the interaction between GRP78 and GRP170 but results in the coprecipitation of an unidentified 60-kDa protein. In addition, GRP170 is found to be coprecipitated with immunoglobulin (Ig) in four different B cell hybridomas expressing surface IgM, cytoplasmic Ig light chain only, cytoplasmic Ig heavy chain only, or an antigen specific secreted IgG. In addition, in IgM surface expressing WEHI-231 B cells, anti-IgM coprecipitates GRP78, GRP94, as well as GRP170; antibodies against GRP170 and GRP94 reciprocally coprecipitate GRP94/GRP170 as well as GRP78. Results suggest that this 170-kDa GRP is a retained ER lumenal glycoprotein that is constitutively present and that may play a role in immunoglobulin folding and assembly in conjunction or consecutively with GRP78 and GRP94.
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PMID:The 170-kDa glucose-regulated stress protein is an endoplasmic reticulum protein that binds immunoglobulin. 830 33

Haptoglobin (Hp), an acute-phase protein, is detected in serum of cows with hepatic lipidosis (fatty liver). To assess the relevance of Hp in fatty liver, induction of Hp was examined, using conditions similar to those involving development of fatty liver in cows. Induction of Hp was achieved by a combination of dexamethasone administration (0.1 mg/kg of body weight) and 2 days' starvation. Haptoglobin appearance in serum was not associated with the increase of alpha 1-acid glycoprotein (a marker for inflammation). This treatment increased serum nonesterified fatty acids concentration and decreased serum triglycerides concentration. Protein kinase C activity was decreased in the cytosolic fractions of liver and mononuclear cells. Reduction of protein kinase C-catalyzed endogenous protein phosphorylation also was observed, particularly in the cytosolic fractions of the tissue and cells. Detection of Hp in serum of cows with fatty liver appears to be explained by the fact that Hp is induced by dexamethasone administration and starvation, which are similar to the condition responsible for fatty liver development. The change of protein kinase C-catalyzed phosphorylation was suggested to be involved in the induction of Hp in cows.
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PMID:Possible involvement of protein kinase C with induction of haptoglobin in cows by treatment with dexamethasone and by starvation. 831 60

Assembly of histocompatibility class I antigens (MHC) with beta 2-microglobulin (beta 2m) and peptide takes place in the rough endoplasmic reticulum (ER). At present, it is unclear why peptides generated in the cytosol or ER by proteolysis are not further degraded. Also, it is an open question whether assembly and/or peptide binding is self-instructive or is promoted by additional molecules, for example, chaperones. We previously demonstrated that the adenovirus glycoprotein E3/19K binds to human and some mouse MHC molecules in the ER, interfering with their transport to the cell surface. Here we show that immunoprecipitates from human cells that express transfected E3/19K and murine MHC Kd molecules not only contain MHC heavy chain, beta 2m and E3/19K but also two additional proteins with apparent molecular weights of 100 kDa and 110 kDa. Biochemical characterization of these proteins, designated p100 and p110, demonstrates that they are transmembrane glycoproteins with a similar if not identical protein backbone. Consistent with a role as chaperones, we find that glucose starvation induces complex formation between p100/110 and MHC-E3/19K. Most interestingly, p100 and p110 are displaced from the complex by addition of Kd-specific peptides. Therefore, p100 and p110 might be chaperones that promote correct folding of MHC antigens and/or peptide binding to MHC.
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PMID:Novel proteins associated with MHC class I antigens in cells expressing the adenovirus protein E3/19K. 834 54

All herpes simplex virus (HSV) infected cell-specific polypeptides (ICSPs) were synthesized in the presence of lithium at a concentration (60 mM) inhibitory to the production of infectious virus. Yields of certain ICSPs were increased and others, in particular glycoprotein C, decreased. HSV DNA synthesis was completely inhibited; synthesis and in vitro activities of HSV DNA polymerase and thymidine kinase were decreased but to a degree insufficient to account for the complete inhibition of HSV DNA synthesis. HSV DNA synthesis was inhibited to an equivalent degree by either incubation with 60 mM-lithium or by potassium starvation; both procedures decreased intracellular potassium by an equivalent amount as adjudged by X-ray microanalysis. We conclude that lithium inhibits HSV DNA synthesis by displacement of potassium from a potassium-dependent biochemical reaction or by other physiological changes brought about by the loss of cellular potassium. The possibility that lithium also directly inhibits a virus replicative event cannot be excluded.
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PMID:The effects of lithium and potassium on macromolecular synthesis in herpes simplex virus-infected cells. 839 11


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