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Phosphorylation and 14-3-3 binding of Arabidopsis trehalose-phosphate synthase 5 in response to 2-deoxyglucose.

Trehalose-6-phosphate is a 'sugar signal' that regulates plant metabolism and development. The Arabidopsis genome encodes trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphatase (TPP) enzymes. It also encodes class II proteins (TPS isoforms 5-11) that contain both TPS-like and TPP-like domains, although whether these have enzymatic activity is unknown. In this paper, we show that TPS5, 6 and 7 are phosphoproteins that bind to 14-3-3 proteins, by using 14-3-3 affinity chromatography, 14-3-3 overlay assays, and by co-immunoprecipitating TPS5 and 14-3-3 isoforms from cell extracts. GST-TPS5 bound to 14-3-3s after in vitro phosphorylation at Ser22 and Thr49 by either mammalian AMP-activated protein kinase (AMPK) or partially purified plant Snf1-related protein kinase 1 (SnRK1s). Dephosphorylation of TPS5, or mutation of either Ser22 or Thr49, abolished binding to 14-3-3s. Ser22 and Thr49 are both conserved in TPS5, 7, 9 and 10. When GST-TPS5 was expressed in human HEK293 cells, Thr49 was phosphorylated in response to 2-deoxyglucose or phenformin, stimuli that activate the AMPK via the upstream kinase LKB1. 2-deoxyglucose stimulated Thr49 phosphorylation of endogenous TPS5 in Arabidopsis cells, whereas phenformin did not. Moreover, extractable SnRK1 activity was increased in Arabidopsis cells in response to 2-deoxyglucose. The plant kinase was inactivated by dephosphorylation and reactivated by phosphorylation with human LKB1, indicating that elements of the SnRK1/AMPK pathway are conserved in Arabidopsis and human cells. We hypothesize that coordinated phosphorylation and 14-3-3 binding of nitrate reductase (NR), 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (F2KP) and class II TPS isoforms mediate responses to signals that activate SnRK1.

14-3-3 Proteins↗

Cloning of two related genes encoding the 56-kDa and 123-kDa subunits of trehalose synthase from the yeast Saccharomyces cerevisiae.

Preparations of intact trehalose synthase contain three polypeptides with molecular masses of 56, 102 and 123 kDa. We have cloned the genes TSS1 and TSL1 coding for the 56- and 123-kDa subunits, respectively. These genes are located on chromosomes II (TSS1) and XIII (TSL1). The TSS1 gene was found to be identical with CIF1, a gene required for normal growth on glucose. The product of the entire TSS1 gene exhibits 37% identity with a 502-amino-acid stretch from the middle of the TSL1 product. Disruption of the TSS1 gene in yeast eliminates both trehalose 6-phosphate synthase (Tre6P synthase) and trehalose 6-phosphate phosphatase (Tre6Pase) activities, and reintroduction of this gene restores these activities. Transformation of Escherichia coli with TSS1 increases its Tre6P synthase activity. Specific proteolytic degradation of the 123-kDa polypeptide from the N-terminus greatly influences the Tre6P synthase activity, decreasing its inhibition by phosphate and activatability by fructose 6-phosphate but has little effect on the Tre6Pase activity. These results suggest that this N-terminal part confers regulatory properties upon the Tre6P synthase activity.

Amino Acid Sequence↗

Production and partial characterization of anti-cord factor (trehalose-6,6'-dimycolate) IgG antibody in rabbits recognizing mycolic acid subclasses of Mycobacterium tuberculosis or Mycobacterium avium.

An ELISA with cord factor (trehalose-6,6'-dimycolate) is useful for the serodiagnosis of tuberculosis. To clarify the exact antigenic epitope in cord factor, recognized by a rabbit anti-cord factor IgG antibody, and to ascertain the most sensitive and specific diagnostic test antigen, rabbits were immunized with two kinds of cord factors isolated from Mycobacterium tuberculosis or Mycobacterium avium and the reactivities of the sera were tested against cord factors or the component mycolic acid methyl esters by ELISA. The serum from rabbits immunized with M. tuberculosis cord factor was highly reactive against M. tuberculosis cord factor, but less reactive against M. avium cord factor. In contrast, the serum from rabbits immunized with M. avium cord factor was highly reactive against M. avium cord factor but less reactive against M. tuberculosis cord factor. Moreover, the serum from rabbits immunized with M. tuberculosis cord factor reacted against mycolic acid methyl esters, especially methoxy mycolic acid methyl ester. On the other hand, the serum from rabbits immunized with M. tuberculosis cord factor was less reactive against trehalose-6-monomycolate and not reactive against sulfolipid (2,3,6,6'-tetraacyl trehalose 2'-sulfate). From these results, it was concluded that the anti-cord factor IgG antibody, produced experimentally in rabbits, recognized the differences in the cord factor structures, i.e. the hydrophobic moiety rather than the carbohydrate moiety. It was also noted that the serum from rabbits immunized with M. tuberculosis cord factor was highly reactive against methoxy mycolic acid as an epitope. This paper is the first to describe how the anti-cord factor IgG antibody can recognize the mycolic acid subclasses, which differ according to the species of mycobacteria.

Animals↗

Effect of growth conditions and trehalose content on cryotolerance of bakers' yeast in frozen doughs.

The cryotolerance in frozen doughs and in water suspensions of bakers' yeast (Saccharomyces cerevisiae) previously grown under various industrial conditions was evaluated on a laboratory scale. Fed-batch cultures were very superior to batch cultures, and strong aeration enhanced cryoresistance in both cases for freezing rates of 1 to 56 degrees C min. Loss of cell viability in frozen dough or water was related to the duration of the dissolved-oxygen deficit during fed-batch growth. Strongly aerobic fed-batch cultures grown at a reduced average specific rate (mu = 0.088 h compared with 0.117 h) also showed greater trehalose synthesis and improved frozen-dough stability. Insufficient aeration (dissolved-oxygen deficit) and lower growth temperature (20 degrees C instead of 30 degrees C) decreased both fed-batch-grown yeast cryoresistance and trehalose content. Although trehalose had a cryoprotective effect in S. cerevisiae, its effect was neutralized by even a momentary lack of excess dissolved oxygen in the fed-batch growth medium.

Journal Article↗

Increased Accumulation of Trehalose in Rhizobia Cultured under 1% Oxygen.

The growth of rhizobia under 1% O(2) induced the accumulation of alpha,alpha-trehalose, and the effect of low O(2) was independent of medium composition and Rhizobium species. Trehalose concentration in cells declined rapidly when microaerobic cultures were supplied with 21% O(2). Trehalose formation in nodules may be induced by the microaerobic environment.

Journal Article↗

Nonspecific resistance against infection with Salmonella typhi and Salmonella typhimurium induced in mice by cord factor (trehalose-6,6'-dimycolate) and its analogues.

Mice pretreated intraperitoneally with trehalose-6,6'-dimycolate (cord factor) were protected against an intraperitoneal challenge with Salmonella typhi strain Ty2 or Salmonella typhimurium strain SR 11. The nonspecific resistance to S. typhi and S. typhimurium was still detectable 7 and 14 days, respectively, after administration of cord factor. The effect of cord factor was local. Synthetic analogues of cord factor--trehalose-6,6'-dipalmitate and trehalose monopalmitate--also induced nonspecific resistance to the above virulent bacteria. The results are discussed.

Animals↗

Nonspecific immunostimulant activities of synthetic trehalose-6,6'-diesters (lower homologs of cord factor).

Mycobacterial cord factors (6,6'-diesters of trehalose with mycolic acids ranging from C80 to C90) have been shown to protect mice effectively against infection with Klebsiella pneumoniae or with Listeria monocytogenes. Our present findings indicate that the low-molecular-weight cord factor of Corynebacterium diphtheriae (with corynomycolic acids ranging from C28 PTO C36) is equally active. Moreover, its synthetic analog (with synthetic C32 mycolic acid) has the same activity. Two lower synthetic 6,6'-diesters of trehalose with C22 acids, which are described here for the first time, as well as dipalmitate and a dioleate of sucrose, were found inactive. The synthetic C76 trehalose diesters, which are capable of enhancing nonspecific resistance to infection, increase the immune response in mice, even when injected in metabolizable oil. They induce in the injected paws an inflammatory process weaker and more transient than the natural cord factor.

Adjuvants, Immunologic↗

Immune response to porin in cattle immunized with whole cell, outer membrane, and outer membrane protein antigens of Brucella abortus combined with trehalose dimycolate and muramyl dipeptide adjuvants.

The immune response of cattle to nonliving vaccines derived from Brucella abortus rough strain 45/20 was studied. Vaccines contained trehalose dimycolate and a derivative of muramyl dipeptide. N-acetylmuramyl-L-alpha-aminobutyryl-D-isoglutamine. A factorial experiment was designed to test the effects of type of antigen, quantity of antigen, and quantity of mineral oil on the immune response to porin. Muramyl dipeptide was kept constant at 5 mg per dose, and 1 part of trehalose dimycolate was incorporated for two parts of dry matter. Over a 10-week period, blastogenesis responses to porin were largest in cattle immunized with outer membranes; the highest antibody titers to the porin-lipopolysaccharide complex were achieved by immunization with detergent-extracted outer membrane proteins. There was no advantage in the use of 25, rather than 5, mg of any of the antigens, but antibody responses were improved by increasing the quantity of oil from 0.6 to 1.8 ml per dose. In other animals, blastogenesis and antibody responses were sustained at high levels longer than 3 months after two vaccinations with outer membrane proteins. Intradermal injection of porin evoked inflammatory reactions histologically consistent with delayed-type hypersensitivity. Cross-reactions in cases of delayed-type hypersensitivity occurred with porin derived from a smooth strain of B. abortus but were less extensive than in the blastogenesis test. The magnitude of the delayed-type hypersensitivity and blastogenesis responses induced by vaccination exceeded those observed after natural or experimental infections. No ill effects were observed after vaccination. These findings provide a basis for the use of trehalose dimycolate and muramyl dipeptide adjuvants in evaluating nonviable vaccines for bovine brucellosis.

Acetylmuramyl-Alanyl-Isoglutamine↗

Partial purification and properties of a highly specific trehalose phosphate phosphatase from Mycobacterium smegmatis.

A specific trehalose phosphate phosphatase was purified approximately 50-fold from Mycobacterium smegmatis. The enzyme had a pH optimum of about 7.0 and was stimulated by Mg(2+). The optimum concentration of Mg(2+) was about 1.5 x 10(-3)m. Of other divalent cations tested, only Co(2+) showed some activity. The K(m) for trehalose phosphate was found to be about 1.5 x 10(-3)m. The enzyme showed slight activity toward mannose-6-P and fructose-6-P but was inactive on a large number of other phosphorylated compounds. Citrate was a competitive inhibitor of the enzyme both with respect to trehalose phosphate concentration and Mg(2+) concentration. This inhibition appears to be due to chelation of Mg(2+) by this compound. Ethylenediaminetetraacetic acid and NaF were also inhibitors of the enzyme, but these inhibitions were noncompetitive.

Calcium Phosphates↗

Trehalose phosphate synthesis in Streptomyces hygroscopicus: purification of guanosine diphosphate D-glucose: D-glucose-6-phosphate 1-glucosyl-transferase.

Guanosine diphosphate d-glucose:d-glucose-6-phosphate 1-glucosyl-transferase was purified approximately 100-fold from extracts of Streptomyces hygroscopicus. The purified enzyme catalyzed the transfer of glucose from guanosine diphosphate-d-glucose to glucose-6-phosphate to form trehalose phosphate and guanosine diphosphate. The enzyme was specific for these two substrates and was stimulated by the addition of magnesium ions. The product was characterized as alpha-alpha-trehalose-6-phosphate by its physical and chemical properties. The enzyme was present in a large number of Streptomyces species, suggesting that this group of organisms synthesized trehalose phosphate in a unique manner. This enzyme was not detected in fungi, since these organisms utilized uridine diphosphate-d-glucose as the glucosyl donor.

Carbon Isotopes↗

Purification and properties of a novel enzyme, maltooligosyl trehalose synthase, from Arthrobacter sp. Q36.

Arthrobacter sp. Q36 produces a novel enzyme, maltooligosyl trehalose synthase, which catalyzes the conversion of maltooligosaccharide into the non-reducing saccharide, maltooligosyl trehalose (alpha-maltooligosyl alpha-D-glucoside) by intramolecular transglycosylation. The enzyme was purified from a cell-free extract to an electrophoretically homogeneous state by successive column chromatography on Sepabeads FP-DA13, DEAE-Sephadex A-50, Ultrogel AcA44, and Butyl-Toyopearl 650M. The enzyme was specific for maltooligosaccharides except maltose, and catalyzed the conversion to form maltooligosyl trehalose. The Km of the enzyme for maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were 22.9 mM, 8.7 mM, 1.4 mM, and 0.9 mM, respectively. The enzyme had a molecular mass of 81,000 by SDS-polyacrylamide gel electrophoresis and a pI of 4.1 by gel isoelectrofocusing. The N-terminal and C-terminal amino acids of the enzyme were methionine and serine, respectively. The enzyme showed the highest activity at pH 7.0 and 40 degrees C, and was stable from pH 6.0 to 9.5 and up to 40 degrees C. The enzyme activity was inhibited by Hg2+ and Cu2+.

Amino Acid Sequence↗

Gene cloning and expression of new trehalose-producing enzymes from the hyperthermophilic archaeum Sulfolobus solfataricus KM1.

The genes encoding for trehalose-producing enzymes, a glycosyl-trehalose-producing enzyme (glycosyltransferase) and a gylcosyl-trehalose-hydrolyzing enzyme (alpha-amylase), from Sulfolobus solfataricus KM1 were cloned and expressed in E. coli. The nucleotide sequence of the glycosyltransferase gene and the alpha-amylase gene indicated proteins with lengths of 728 and 558 amino acids and molecular masses of 86-kDa and 65-kDa, respectively. Regions highly conserved in the alpha-amylase family exist in the amino acid sequences of these enzymes.

Amino Acid Sequence↗

Gene encoding a trehalose phosphorylase from Thermoanaerobacter brockii ATCC 35047.

A gene encoding a trehalose phosphorylase was cloned from Thermoanaerobacter brockii ATCC 35047. The gene encodes a polypeptide of 774 amino acid residues. The deduced amino acid sequence was homologous to bacterial maltose phosphorylases and a trehalose 6-phosphate phosphorylase catalyzing anomer-inverting reactions. On the other hand, no homology was found between the T. brockii enzyme and an anomer-retaining trehalose phosphorylase from Grifola frondosa.

Amino Acid Sequence↗

Molecular cloning, characterization and expression of a novel trehalose-6-phosphate synthase homologue from Ginkgo biloba.

In many organisms, trehalose acts as protective metabolite against harsh environmental stresses, such as freezing, drought, nutrient starvation, heat and salt. Herein a cDNA (designated as GbTPS, GenBank Accession Number AY884150) encoding a trehalose-6-phosphate synthase homologue was isolated and characterized from the living fossil plant, Ginkgo biloba, which is highly tolerant to drought and cold. GbTPS encoded an 868-amino-acid polypeptide with a predicted isoelectric point of 5.83 and molecular mass of 97.9 kD. Amino acid sequence alignment revealed that GbTPS shared high identity with class II trehalose-6-phosphate synthase homologues (67% identical to AtTPS7), but had only 17% and 23% of identity with OstA from Escherichia coli and ScTPS1 from S. cerevisiae, respectively. DNA gel blot analysis indicated that GbTPS belonged to a small multi-gene family. The expression analysis by RT-PCR showed that GbTPS expressed in a tissue-specific manner in G. biloba and might involve in leaf development. GbTPS was also found to be induced by a variety of stresses including cold, salt, drought and mannitol.

Amino Acid Sequence↗

[Cloning and expression of trehalose synthase genes in Escherchia coli].

Escherichia coli trehalose synthase otsBA genes have been cloned by using transposon Mu in vivo. The cloning frequency was 1.45 x 10(-3)/Kanr transductant. Genetic complements, endonuclase digestion and partial nucleotide sequencing analysis of these clones indicated that otsBA gene was on plasmid Mud5005. Subcloning 2.87 kb DNA fragment onto expression plasmids with higher or lower copy number and transforming into E. coli recipient strain FF4050, which have otsBA genes deleted respectively, the transformed strains obtained ability of growth on medium containing 0.5 mol/L NaCl and increased trehalose synthesis under high osmotic pressure. Production and accumulation of trehalose may play an important role in crop breeding. These studies will lay an important foundation for constructing an expression vector with the otsBA genes and transformation to tobacco mediated by Agrobacterium, and obtaining ability for drought resistance and high osmotic pressure tolerance.

Cloning, Molecular↗

Soluble carbohydrates (trehalose in particular) and cryoprotection in polar biota.

Data are presented here on low molecular weight carbohydrates contents (assessed from samples collected in situ) of selected, representative terrestrial species from the maritime Antarctic. Significant seasonal variation for most species were observed. Increased levels overwinter in arthropods contrasted with cryptogams where levels were higher in spring and summer samples. The occurrence and seasonal variation of trehalose in particular is demonstrated for invertebrate and lichen species. The data are discussed in relation to published results from experimental manipulation of growth temperatures on Antarctic fungi and an Arctic springtail providing further evidence for the protective role of trehalose. The widespread presence of trehalose in polar biota is documented and discussed regarding acclimatisation to both low temperature and partial dehydration.

Journal Article↗

[Identification of trehalose-phosphate phosphatase associated with drug-resistance from culture supernatants of isoniazid-resistant Mycobacterium tuberculosis].

OBJECTIVE: To isolate and identify a new protein involved in drug-resistance from culture supernatants of isoniazid (INH)-resistant Mycobacterium tuberculosis. METHODS: Bovine albumin of Middlebrook 7H10 culture supernatants of INH-resistant Mycobacterium tuberculosis was removed using diethylamine ethylcellulose affinitive gel chromatography. A specific protein from culture supernatants of three INH-resistant Mycobacterium tuberculosis isolates was separated reproducibly by high performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide electrophoresis, and identified by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-MS). RESULTS: The protein was trehalose-phosphate phosphatase involved in the biosynthesis of trehalose of cell wall, molecular a eight 46000, isoelectric point 5.3. It could be detected repeatedly from supernatants of three INH resistant Mycobacterium tuberculosis isolates. CONCLUSION: Trehalose-phosphate phosphatase represents an excellent potential target site for chemotherapy against Mycobacterium tuberculosis and a new marker in the detection of drug resistance of Mycobacterium tuberculosis.

Animals↗

The high general stress resistance of the Saccharomyces cerevisiae fil1 adenylate cyclase mutant (Cyr1Lys1682) is only partially dependent on trehalose, Hsp104 and overexpression of Msn2/4-regulated genes.

The initiation of fermentation in the yeast Saccharomyces cerevisiae is associated with a rapid drop in general stress resistance. Previously we identified a mutant which is deficient in fermentation-induced loss of stress resistance (fil1), as a partially inactivating mutant in adenylate cyclase. We have now investigated possible causes of its high stress resistance. Deletion of the TPS1 gene, encoding the first enzyme in the biosynthesis of trehalose, or the heat shock protein gene HSP104 only resulted in a minor effect on heat stress resistance compared with deletion of these genes in a wild-type background. A strain with a deletion of both genes still showed a higher stress resistance in the fil1 background compared to the corresponding wild-type background. Deletion of the transcription factor genes MSN2 and MSN4, which are required for the expression of STRE-regulated genes, resulted in a dramatic drop in heat resistance in the wild-type background but had much less effect in the fil1 mutant. The fil1 msn2Deltamsn4Delta strain remained more heat-resistant than a wild-type strain. A strain in which all four genes, TPS1, HSP104, MSN2 and MSN4, are deleted was very sensitive to heat stress and also to oxidative and salt stress. Presence of the fil1 mutation in such a strain, however, still clearly enhanced heat, oxidative and salt stress resistance. These results indicate that, in addition to trehalose, Hsp104 and the Msn2/4-controlled genes, other factors exist in S. cerevisiae that can, significantly and independently of the known factors, enhance general stress resistance. The mutants described in this work provide a tool to identify these novel components.

Adenylyl Cyclases↗