Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chryseobacterium meningosepticum is an aerobic Gram-negative rod widely distributed in natural environments. Unlike many bacteria, it produces a phosphate-irrepressible periplasmic alkaline phosphatase (AP). This work describes cloning of the gene encoding that enzyme from C. meningosepticum CCUG 4310 (NCTC 10585), and preliminary characterization of its product. The gene, named pafA, encodes a protein (PafA) of 546 amino acids with a calculated molecular mass of the mature peptide of 58682 Da. PafA exhibits high sequence identity with the PhoV AP of Synechococcus PCC 7942 (49.9% identity) and with the Cda Ca(2+)-dependent ATPase of Myroides odoratus (51.9% identity), while being more distantly related to the PhoD AP of Zymomonas mobilis (22.1% identity) and to the PhoA AP of Escherichia coli (14.0% identity). PafA was partially purified; it exhibits optimal activity at pH 8.5 and is active towards a broad spectrum of substrates including both phosphomonoesters and ATP, with preferential activity for the latter compound. The present findings allow definition of a new family of APs including 60 kDa, periplasmic enzymes whose expression is not influenced by freely available P(i) in the medium. Moreover, PafA can be considered an evolutionary intermediate between Ca(2+)-ATPase of M. odoratus and the APs PhoV of Synechococcus PCC 7942 and PhoD of Z. mobilis.
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PMID:The Chryseobacterium meningosepticum PafA enzyme: prototype of a new enzyme family of prokaryotic phosphate-irrepressible alkaline phosphatases? 1157 61

Massive growth of cyanobacteria, known as "algal blooms", has become a major concern for water monitoring. It has been observed that environmental factors like temperature, light, and certain patterns of availability of nutrients such as P, N, Fe influence cyanobacterial proliferation and toxin production. In order to monitor nutrients in aquatic ecosystems, an assay for monitoring phosphorus bioavailability to cyanobacteria was developed. The test consists of an immobilized luminescent reporter strain of Synechococcus PCC 7942, designated APL. The reporter strain harbours the gene coding the reporter protein luciferase from Vibrio harveyi under control of the inducible alkaline phosphatase promoter from Synechococcus PCC 7942, and can be induced under phosphorus limitation. The resultant CyanoSensor detects PO(3-)(4)-P in a concentration range of 0.3-8 microM after a sample incubation time of 8 h under continuous illumination (50 microE m(-2) s(-1)). The sensor also responded to a variety of organic phosphorus sources and was storable for 3 weeks at 4 degrees C. It could be demonstrated that the CyanoSensor for bioavailability monitoring is an improvement to conventional phosphorus detection methods.
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PMID:Monitoring of phosphorus bioavailability in water by an immobilized luminescent cyanobacterial reporter strain. 1167 59

In the cyanobacterium Calothrix sp. PCC 7601 the cpc2 operon encoding phycocyanin 2 (PC2) is expressed if red radiations are available. RcaD was previously identified in extracts from red-light-grown cells as an alkaline phosphatase-sensitive protein that binds upstream of the transcription start point (TSP) of the cpc2 operon. In this work, RcaD was purified, and the corresponding gene cloned with a PCR probe obtained using degenerated primers based on RcaD peptide sequences (accession no. AJ319541). Purified RcaD binds to the cpc2 promoter region and also to those of the constitutive cpc1 and apc1 operons that encode phycocyanin 1 and allophycocyanin. Escherichia coli-overexpressed RcaD can bind to the cpc2 promoter region. The rcaD gene is upstream of an open reading frame (ORF) termed rcaG. Co-transcription of both genes was demonstrated by reverse transcription (RT)-PCR experiments, and found to be independent of the light wavelengths. A single TSP was mapped. Sequence features of RcaD and RcaG led us to propose a functional relationship between these two proteins. A rcaD mutant generated by allelic exchange exhibited altered expression of the cpc2, cpeBA, apc1 and cpc1 operons upon green to red-light shifts. RcaD seems to be a co-activator co-ordinating the transcription of the phycobiliprotein operons upon changes in light spectral quality.
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PMID:Co-ordinated expression of phycobiliprotein operons in the chromatically adapting cyanobacterium Calothrix PCC 7601: a role for RcaD and RcaG. 1192 29

We review the basic functions of neurotrophins and their receptors and discuss the expression and functions of neurotrophins and their specific receptors based on recent data using cultured cells from human periodontal tissues. Neurotrophins, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) play crucial roles in the differentiation and survival of neural cells. Neurotrophins activate 2 different receptor classes: the tropomyosin-related kinase (Trk) family of receptor tyrosine kinases (TrkA, TrkB, and TrkC) and the p75 receptor, a member of the tumor necrosis factor receptor superfamily. Neurotrophins regulate both cell death and cell survival through activations of Trk receptors and/or p75 neurotrophin receptor. It has been reported that neurotrophins are also produced from non-neuronal cells, such as leukocytes, osteoblasts, or fibroblasts, and act in many other ways on non-neuronal cells. Neurotrophin expression during bone fracture healing is especially interesting, and neurotrophins are now implicated in hard tissue regeneration. It is well known that neurotrophins and their receptors are expressed in tooth development. Recent studies have found that neurotrophins and Trk receptors are expressed in mouse osteoblastic cell lines. Human periodontal ligament cells, human gingival fibroblasts, and human gingival keratinocytes expressed mRNA for NGF and TrkA. The secretion of bioactive NGF peptides from human periodontal ligament cells and human gingival keratinocytes was confirmed by bioassay using PC12 cells (rat adrenal pheochromocytoma cells). The expression of NGF and TrkA.mRNA was regulated by interleukin (IL)-1beta. NGF increased DNA synthesis and expressions of mRNA for bone-related proteins, alkaline phosphatase, and osteopontin in human periodontal ligament cells. Neurotrophins and Trk receptors expressed in human periodontal tissue may contribute to regeneration as well as innervation of periodontal tissue through local autocrine and paracrine pathways. Recent data suggest that some functions of neurotrophins and Trk receptors relate to periodontal disease and periodontal tissue regeneration. However, in vivo studies will be required to clarify the roles of neurotrophins and their receptors, including p75, in periodontal disease and periodontal tissue regeneration.
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PMID:Neurotrophins in cultured cells from periodontal tissues. 1259

Living organisms respond to phosphate limitation by expressing various genes whose products maintain an appropriate range of phosphate concentrations within each cell. We identified previously a two component system, which consists of histidine kinase SphS and its cognate response regulator SphR, which regulates the expression of the phoA gene for alkaline phosphatase under phosphate-limiting conditions in the cyanobacterium Synechocystis sp. PCC 6803. In the present study, we used DNA microarrays to investigate the role of SphS and SphR in the regulation of the genome-wide expression of genes in response to phosphate limitation. In wild-type cells, phosphate limitation strongly induced the expression of 12 genes with induction factors greater than 7. These genes were included in three clusters of genes, namely, the pst1 and pst2 clusters that encode phosphate transporters; the phoA gene and the nucH gene for the extracellular nuclease. Phosphate limitation strongly repressed the expression of only the urtA gene with induction factors below 0.2. Inactivation of either of SphS or SphR completely eliminated the phosphate limitation-inducible expression of the 12 genes and the phosphate limitation-repressible expression of the urtA gene. These results suggest that the SphS-SphR two component system in Synechocystis sp. PCC 6803 is the dominant sensory system that controls gene expression in response to phosphate limitation.
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PMID:The SphS-SphR two component system is the exclusive sensor for the induction of gene expression in response to phosphate limitation in synechocystis. 1470 28

A 72-year-old woman with von Recklinghausen's disease was referred to our hospital because of pain and muscle weakness in her thighs. She had elevated serum values of creatine kinase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and aldolase. Based on these results, a diagnosis of polymyositis was made. Treatment with prednisolone improved muscle strength, and laboratory values returned to normal. Computed tomography, magnetic resonance imaging of the abdomen, and 131I-metaiodobenzyl guanidine MIBG scintigraphy demonstrated a tumor 3 cm in diameter in the region of the left adrenal gland. Endocrinologic investigation disclosed elevation of serum and urine catecholamines. Since the blood pressure was normal, nonfunctioning pheochromocytoma was diagnosed clinically. The nonhypertensive course was attributed to reduced vascular response to noradrenaline. Serum lactate dehydrogenase. alkaline phosphatase. and asparate aminotransferase became elevated, and abdominal computed tomography showed a well-defined mass measuring 13 x 12 x 10 cm in the right lobe of the liver. The patient underwent right trisegmentectomy and left adrenalectomy. Histologically the adrenal tumor was a typical pheochromocytoma. The hepatic tumor was a leiomyosarcoma consisting of elongated spindle-shaped atypical cells arranged in intersecting bundles. Immunohistochemically, the cells of this tumor were reactive for alpha-smooth muscle actin and vimentin. The leiomyosarcoma recurred and metastasized to the liver. Eight months after onset of symptom, the patient developed hepatic coma and died. The mean age at presentation with pheochromocytoma in von Recklinghausen's disease patients age is 42 years. Our patient was considerably older. To the best of our knowledge this is the first report of a patient with von Recklinghausen's disease developing polymyositis. asymptomatic pheochromocytoma, and primary hepatic leiomyosarcoma and illustrates the need to remain aware of the possibility of cancer in von Recklinghausen's disease.
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PMID:[A patient with von Recklinghausen's disease associated with polymyositis, asymptomatic pheochromocytoma, and primary hepatic leiomyosarcoma]. 1523 55

The Pho regulon is controlled by the histidine kinase-response regulator pair SphS-SphR in many cyanobacteria and up-regulation of the Pho regulon can be monitored by measuring alkaline phosphatase activity. However, the mechanism regulating signal transduction between SphS and SphR has not been described. We have created a cyanobacterial strain allowing the introduction of mutations into the transmitter domain of SphS. Mutations at Thr-167, adjacent to the H motif of SphS, introduce elevated alkaline phosphatase activity in the presence of phosphate and an enhancement of alkaline phosphatase activity, when compared to the control strain, in phosphate-limiting media. SphU acts as a negative regulator of the SphS-SphR system in Synechocystis sp. PCC 6803 and we show that constitutive alkaline phosphatase activity in the absence of SphU requires signal transduction through SphS and SphR. However, constitutive activity in the absence of SphU is severely attenuated in the DeltaSphU:SphS-T167N mutant. Our data suggest that Thr-167 contributes to the mechanism underlying regulation by SphU. We have also assembled a deletion mutant system allowing the introduction of mutations into SphR and show that Gly-225 and Trp-236, which are both conserved in SphR from cyanobacteria, are essential for activation of the Pho regulon under phosphate-limiting conditions.
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PMID:Phosphate sensing in Synechocystis sp. PCC 6803: SphU and the SphS-SphR two-component regulatory system. 1754 76

In Synechocystis sp. PCC 6803 extracellular phosphate levels are relayed to the pho regulon via the SphS histidine kinase. In this cyanobacterium, the start codon of sphS has been assigned as a GUG, thereby predicting SphS to be a cytosolic protein lacking a putative N-terminal region found in the PhoR orthologue from Escherichia coli. Inspection upstream of sphS located an in-frame AUG positioned 47 codons in front of the putative GUG start. Alterations at either of the putative AUG or GUG start codons did not prevent transcription of sphS; however, up-regulation of alkaline phosphatase mRNA, or alkaline phosphatase activity, was not detected in response to phosphate-limiting conditions when the AUG was mutated. Alkaline phosphatase expression and activity serve as phenotypic markers for activation of the pho regulon. Therefore, the pho regulon had not been induced in these cells, whereas normal up-regulation was observed in strains carrying mutations at the GUG. These results show that the AUG codon, not the GUG codon, is the initiation site for sphS translation in Synechocystis sp. PCC 6803.
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PMID:Identification of the start codon for sphS encoding the phosphate-sensing histidine kinase in Synechocystis sp. PCC 6803. 1757 13

The two-component signal transduction, which typically consists of a histidine kinase and a response regulator, is used by bacterial cells to sense changes in their environment. Previously, the SphS-SphR histidine kinase and response regulator pair of phosphate sensing signal transduction has been identified in Synechocystis sp. PCC 6803. In addition, some response regulators in bacteria have been shown to be cross regulated by low molecular weight phosphorylated compounds in the absence of the cognate histidine kinase. The ability of an endogenous acetyl phosphate to phosphorylate the response regulator, SphR in the absence of the cognate histidine kinase, SphS was therefore tested in Synechocystis sp. PCC 6803. The mutant lacking functional SphS and acetate kinase showed no detectable alkaline phosphatase activity under phosphate-limiting growth conditions. The results suggested that the endogenous acetyl phosphate accumulated inside the mutants could not activate the SphR via phosphorylation. On the other hand, exogenous acetyl phosphate could allow the mutant lacking functional acetate kinase and phosphotransacetylase to grow under phosphate-limiting conditions suggesting the role of acetyl phosphate as an energy source. Reverse transcription PCR demonstrated that the transcripts of acetate kinase and phosphotransacetylase genes in Synechocystis sp. PCC 6803 is upregulated in response to phosphate limitation suggesting the importance of these two enzymes for energy metabolism in Synechocystis cells.
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PMID:Two-component signal transduction in Synechocystis sp. PCC 6803 under phosphate limitation: role of acetyl phosphate. 1792 4

A novel 47 amino acid extension at the N-terminus of the SphS histidine kinase has been identified in the cyanobacterium Synechocystis sp. PCC 6803. Here, we demonstrate this region is required for activation of the SphS-SphR phosphate-sensing two-component system under phosphate-limiting conditions and mutants lacking this extension do not show constitutive alkaline phosphatase activity when the negative regulator SphU is inactivated. We have also identified a putative membrane-associated domain within this region involved in control of the Pho regulon. In addition, there are two high-affinity ABC-type phosphate uptake systems in this organism. Our results demonstrate that the Pst1 system, but not the Pst2 system, is required for suppression of the Pho regulon under phosphate-sufficient conditions. Deletion of the pst1 operon and disruption of the membrane-spanning domain may both target the same control mechanism since constitutive alkaline phosphatase activity is similar in the double and single mutants.
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PMID:The extended N-terminal region of SphS is required for detection of external phosphate levels in Synechocystis sp. PCC 6803. 1901 33


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