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)

Two criteria are suggested for assessing the relevance of biochemical events occurring early in sporulation. The first is thymidine starvation, a condition known to inhibit sporulation. This also inhibits the production of metalloprotease, serine protease, and ribonuclease; alpha-amylase production, however, is unaffected. The second is the effect of a regulator mutation which increases the production of the proteases. In the mutant, ribonuclease is produced in correspondingly large quantities whereas alpha-amylase production is unaffected. We conclude that, whereas the serine protease is part of the main sequence of events leading to formation of the spore, the metalloprotease is a side effect, i.e., connected with the main sequence but not part of it. Ribonuclease could, on present evidence, be either in the main sequence or a side effect associated with it. Amylase, however, seems to be separately regulated and neither directly nor indirectly connected with the sporulation sequence.
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PMID:Criteria for categorizing early biochemical events occurring during sporulation of Bacillus subtilis. 80 78

omega 4403 is the site of a Tn5 lac insertion in the Myxococcus xanthus genome that fuses lacZ expression to a developmentally regulated promoter. Cell-cell interactions that occur during development, including C-signaling, are required for expression of Tn5 lac omega 4403. We have cloned DNA upstream of the omega 4403 insertion site, localized the promoter, and identified a potential open reading frame. From the deduced amino acid sequence, the gene disrupted by Tn5 lac omega 4403 appears to encode a serine protease that is dispensable for development. The gene begins to be expressed between 6 and 12 h after starvation initiates development, as determined by measuring mRNA or beta-galactosidase accumulation in cells containing Tn5 lac omega 4403. The putative transcriptional start site was mapped, and sequences centered near -10 and -35 bp relative to this site show some similarity to the corresponding regions of promoters transcribed by Escherichia coli sigma70 RNA polymerase. However, deletions showed that an essential promoter element lies between -80 and -72 bp, suggesting the possible involvement of an upstream activator protein. DNA downstream of -80 is sufficient for C-signal-dependent activation of this promoter. The promoter is not fully expressed when fusions are integrated at the Mx8 phage attachment site in the chromosome. Titration of a limiting factor by two copies of the regulatory region (one at the attachment site and one at the native site) can, in part, explain the reduced expression. We speculate that the remaining difference may be due to an effect of chromosomal position. These results provide a basis for studies aimed at identifying regulators of C-signal-dependent gene expression.
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PMID:Characterization of the regulatory region of a cell interaction-dependent gene in Myxococcus xanthus. 862 20

An endopeptidase (designated RSIP, for root-starvation-induced protease) was purified to homogeneity from glucose-starved maize roots. The molecular mass of the enzyme was 59 kDa by SDS/PAGE under reducing conditions and 62 kDa by gel filtration on a Sephacryl S-200 column. The isoelectric point of RSIP was 4.55. The purified enzyme was stable, with no auto-proteolytic activity. The enzyme activity was strongly inhibited by proteinaceous trypsin inhibitors, di-isopropylfluorophosphate, 3,4-dichloroisocoumarin and PMSF, suggesting that the enzyme is a serine protease. The maximum proteolytic activity against different protein substrates occurred at pH 6.5. With the exception of succinyl-Leu-Leu-Val-Tyr-4-methylcoumarin, no hydrolysis was detected with synthetic tryptic, chymotryptic or peptidylglutamate substrates. The determination of the cleavage sites in the oxidized B-Chain of insulin showed specificity for hydrophobic residues at the P2 and P3 positions, indicating that RSIP is distinct from other previously characterized maize endopeptidases. Both subcellular fractionation and immuno-detection in situ indicated that RSIP is localized in the vacuole of the root cells. RSIP is the first vacuolar serine endopeptidase to be identified. Glucose starvation induced RSIP: after 4 days of starvation, RSIP was estimated to constitute 80% of total endopeptidase activity in the root tip. These results suggest that RSIP is implicated in vacuolar autophagic processes triggered by carbon limitation.
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PMID:Purification and biochemical characterization of a vacuolar serine endopeptidase induced by glucose starvation in maize roots. 894 99

The haloalkaliphilic archaeon Natronococcus occultus produces an extracellular serine protease in the stationary growth phase and upon starvation. Two proteins immunologically related to the extracellular protease were detected into the cells: P200 and P190. P200 was detected at early stages of growth and its relative amount decreased as the culture reached the stationary growth phase, concomitantly with the appearance of P190 and proteolytic activity, suggesting that P200 may be the precursor of the secreted protease and P190 the mature enzyme. Both proteins were also detected in the culture medium. Conversion of inactive P200 into active P190 was attained in cell-free culture medium from stationary phase but not from exponential phase. This process was prevented in the presence of PMSF and could be attained by addition of purified mature extracellular protease to P200. Altogether these results indicate that activation of Natronococcus occultus extracellular protease may be autoproteolytic and that factor/s present in stationary phase culture medium may be required for this process.
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PMID:Autoproteolytic activation of the haloalkaliphilic archaeon Natronococcus occultus extracellular serine protease. 1180 42

A serine protease gene designated Pyrenopeziza brassicae serine protease 2 (Psp2) was cloned from the plant pathogenic fungus Pyrenopeziza brassicae and its expression analysed. Psp2 was transcribed in equal levels during both vegetative growth and sexual development and showed no differential expression in the presence of exogenous protein or during starvation.
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PMID:Cloning and expression studies during vegetative growth and sexual development of Psp2, a serine protease gene from Pyrenopeziza brassicae. 1215 Nov 10

Upon starvation Bacillus subtilis undergoes a developmental process involving creation of two cell types, the mother cell and forespore. A signal in the form of a serine protease, SpoIVB, is secreted from the forespore and leads to regulated intramembrane proteolysis (RIP) of pro-sigmaK, releasing active sigmaK into the mother cell. RIP of pro-sigmaK is carried out by a membrane-embedded metalloprotease, SpoIVFB, which is inactive when bound by BofA and SpoIVFA. We have investigated the mechanism by which this complex is activated. By expressing components of the signalling pathway in Escherichia coli, we reconstructed complete inhibition of pro-sigmaK RIP by BofA and SpoIVFA, and found that SpoIVB serine protease activity could partially restore RIP, apparently by targeting SpoIVFA. Pulse-chase experiments demonstrated that SpoIVFA synthesized early during B. subtilis sporulation is lost in a SpoIVB-dependent fashion, coincident with the onset of pro-sigmaK RIP, supporting the idea that SpoIVB targets SpoIVFA to trigger RIP of pro-sigmaK. Loss of BofA depended not only on SpoIVB, but also on CtpB, a serine protease secreted from the mother cell. CtpB appeared to cleave BofA near its C-terminus upon coexpression in E. coli, and purified CtpB degraded BofA. We propose that RIP of pro-sigmaK involves a three-step proteolytic cascade in which SpoIVB first cleaves SpoIVFA, CtpB then cleaves BofA and finally SpoIVFB cleaves pro-sigmaK.
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PMID:Serine proteases from two cell types target different components of a complex that governs regulated intramembrane proteolysis of pro-sigmaK during Bacillus subtilis development. 1623 31

Bacillus subtilis responds to phosphate starvation stress by inducing the PhoP and SigB regulons. While the PhoP regulon provides a specific response to phosphate starvation stress, maximizing the acquisition of phosphate (P(i)) from the environment and reducing the cellular requirement for this essential nutrient, the SigB regulon provides nonspecific resistance to stress by protecting essential cellular components, such as DNA and membranes. We have characterized the phosphate starvation stress response of B. subtilis at a genome-wide level using DNA macroarrays. A combination of outlier and cluster analyses identified putative new members of the PhoP regulon, namely, yfkN (2',3' cyclic nucleotide 2'-phosphodiesterase), yurI (RNase), yjdB (unknown), and vpr (extracellular serine protease). YurI is thought to be responsible for the nonspecific degradation of RNA, while the activity of YfkN on various nucleotide phosphates suggests that it could act on substrates liberated by YurI, which produces 3' or 5' phosphoribonucleotides. The putative new PhoP regulon members are either known or predicted to be secreted and are likely to be important for the recovery of inorganic phosphate from a variety of organic sources of phosphate in the environment.
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PMID:Genome-wide transcriptional analysis of the phosphate starvation stimulon of Bacillus subtilis. 1629 80

Schizosaccharomyces pombe isp6(+) gene encodes a vacuolar serine protease, which is specifically induced during nitrogen starvation. An isp6-disruption mutant, isp6Delta, grew normally under normal conditions but was defective in large-scale protein degradation during nitrogen starvation, a hallmark of autophagy. Vacuoles are the organelles for such drastic protein degradation but those of isp6Delta were apparently aberrant. isp6Delta was infertile under nitrogen source-free conditions with poor expression of ste11(+), a gene critical for sexual development. A protein kinase A-disruption mutant, pka1Delta, is prone to sexual development because expression of ste11(+) is derepressed. However, isp6Deltapka1Delta still showed defects in ste11(+) expression and sexual development under nitrogen source-free conditions. isp6Delta and isp6Deltapka1Delta were able to initiate sexual development to produce spores when only a small amount of a nitrogen source was present. Pat1 protein kinase negatively controls meiosis, and a temperature-sensitive mutant of pat1, pat1-114, initiates meiosis irrespective of ploidy at the restrictive temperature. However, isp6Deltapat1-114 did not start meiosis under nitrogen source-free conditions even at the restrictive temperature. These observations suggest that isp6(+) contributes to sexual development by providing a nitrogen source through autophagy.
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PMID:A starvation-specific serine protease gene, isp6+, is involved in both autophagy and sexual development in Schizosaccharomyces pombe. 1655 Mar 52

Efficient regulation of nitrogen metabolism likely plays a role in the ability of fungi to exploit ecological niches. To learn about regulation of nitrogen metabolism in the rice blast pathogen Magnaporthe grisea, we undertook a genome-wide analysis of gene expression under nitrogen-limiting conditions. Five hundred and twenty genes showed increased transcript levels at 12 and 48 h after shifting the fungus to media lacking nitrate as a nitrogen source. Thirty-nine of these genes have putative functions in amino acid metabolism and uptake, and include the global nitrogen regulator in M. grisea, NUT1. Evaluation of seven nitrogen starvation-induced genes revealed that all were expressed during rice infection. Targeted gene replacement on one such gene, the vacuolar serine protease, SPM1, resulted in decreased sporulation and appressorial development as well as a greatly attenuated ability to cause disease. Data are discussed in the context of nitrogen metabolism under starvation conditions, as well as conditions potentially encountered during invasive growth in planta.
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PMID:Global gene expression during nitrogen starvation in the rice blast fungus, Magnaporthe grisea. 1673 Oct 15

We have previously reported the occurrence of two serine endoproteases (referred to as P1 and P2) in dark-induced senescent wheat (Triticum aestivum L.) leaves. P1 enzyme was already purified and identified as a subtilisin-like serine endoprotease (Roberts et al. in Physiol Plant 118:483-490, 2003). In this paper, we demonstrate by Western blot analysis of extracts obtained from dark-induced senescent leaves that an antiserum raised against P1 was able to recognise a second protein band of 78 kDa which corresponded to P2 activity. This result suggested that both enzymes must be structurally related. Therefore, we purified and characterised P2 activity. According to its biochemical and physical properties (inhibition by chymostatin and PMSF, broad pH range of activity, thermostability and ability to hydrolyse Suc-AAPF-pNA) P2 was classified as a serine protease with chymotrypsin-like activity. In addition, P2 was identified by mass spectrometry as a subtilisin-like protease distinct from P1. Western blot analysis demonstrated that P1 appeared in extracts from non-detached dark-induced senescent leaves but was undetectable in leaves senescing after nitrogen (N) deprivation. In contrast, P2 was already present in non-senescent leaves and showed increased levels in leaves senescing after N starvation or incubation in darkness. P1 signal was detected at late stages of ethephon or methyl jasmonate-induced senescence but was undetectable in senescent leaves from plants treated with abscisic acid. None of the three hormones have any effect on P2 protein levels. These results indicate that despite their biochemical and structural similarities, both enzymes are probably involved in different physiological roles.
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PMID:The two main endoproteases present in dark-induced senescent wheat leaves are distinct subtilisin-like proteases. 1674 46


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