Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Sugar signaling is a mechanism that plants use to integrate various internal and external cues to achieve nutrient homeostasis, mediate developmental programs, and articulate stress responses. Many bZIP transcription factors are known to be involved in nutrient and/or stress signaling. An Arabidopsis S1-group bZIP gene, AtbZIP1, was identified as a sugar-sensitive gene in a previous gene expression profiling study (Plant Cell. 16, 2128-2150). In this report, we show that the expression of AtbZIP1 is repressed by sugars in a fast, sensitive, and reversible way. The sugar repression of AtbZIP1 is affected by a conserved sugar signaling component, hexokinase. Besides being a sugar-regulated gene, AtbZIP1 can mediate sugar signaling and affect gene expression, plant growth, and development. When carbon nutrients are limited, gain or loss of function of AtbZIP1 causes changes in the rates of early seedling establishment. Results of phenotypic analyses indicate that AtbZIP1 acts as a negative regulator of early seedling growth. Using gain- and loss-of-function plants in a microarray analysis, two sets of putative AtbZIP1-regulated genes have been identified. Among them, sugar-responsive genes are highly over-represented, implicating a role of AtbZIP1 in sugar-mediated gene expression. Using yeast two-hybrid (Y-2-H) screens and bimolecular fluorescence complementation (BiFC) analyses, we are able to recapitulate extensive C/S1 AtbZIP protein interacting network in living cells. Finally, we show that AtbZIP1 can bind ACGT-based motifs in vitro and that the binding characteristics appear to be affected by the heterodimerization between AtbZIP1 and the C-group AtbZIPs, including AtbZIP10 and AtbZIP63.
 ...
PMID:The arabidopsis bZIP1 transcription factor is involved in sugar signaling, protein networking, and DNA binding. 2008 Aug 16

Sugars play important roles as both nutrients and regulatory molecules throughout plant life. Sugar metabolism and signalling function in an intricate network with numerous hormones and reactive oxygen species (ROS) production, signalling and scavenging systems. Although hexokinase is well known to fulfil a crucial role in glucose sensing processes, a scenario is emerging in which the catalytic activity of mitochondria-associated hexokinase regulates glucose-6-phosphate and ROS levels, stimulating antioxidant defence mechanisms and the synthesis of phenolic compounds. As a new concept, it can be hypothesized that the synergistic interaction of sugars (or sugar-like compounds) and phenolic compounds forms part of an integrated redox system, quenching ROS and contributing to stress tolerance, especially in tissues or organelles with high soluble sugar concentrations.
 ...
PMID:Sugar signalling and antioxidant network connections in plant cells. 2041 56

Freeze-drying is commonly used to preserve probiotics, but it could cause cell damage and loss of viability. The cryoprotectants play an important role in the conservation of viability during freeze-drying. In this study, we investigated the survival rates of Lactobacillus reuteri CICC6226 in the presence of cryoprotectants such as sucrose, trehalose, and reconstituted skim milk (RSM). In addition, we determined the activities of hexokinase (HK), pyruvate kinase (PK), lactate dehydrogenase (LDH), and ATPases immediately following the freeze-drying. The results showed that the differences in HK and PK activities with and without the cryoprotectants during freeze-drying were not significant, but cell viability and activities of LDH and ATPase were significantly different (P<0.01) prior to and after freeze-drying. Meanwhile, the results showed that the maintenance of the membrane integrity and fluidity was improved in the presence of the 10% trehalose or 10% RSM than other treatments during freeze-drying. These results have provided direct biochemical and metabolic evidence of injured cell during freeze-drying. Freeze-drying damaged membrane structure and function of cell and inactivated enzymes (LDH and ATPases). The results imply that LDH and ATPases are key markers and could be used to evaluate the effect of cryoprotectants on viability and metabolic activities of L. reuteri CICC6226 during freeze-drying.
 ...
PMID:Effects of cryoprotectants on viability of Lactobacillus reuteri CICC6226. 2162 24

The purpose of this study was to evaluate differences in histological subtypes of lung cancer using (18)F-FDG-PET 3-point imaging and kinetic analysis. Subjects comprised 44 patients with histologically proven lung cancer (squamous cell carcinoma (SCC), n=18; well-differentiated adenocarcinoma (WDA), n=9; poorly/moderately differentiated adenocarcinoma (non-WDA), n=17) who underwent (18)F-FDG-PET/CT examinations at 1, 2 h and 3 h after injection of 185 MBq of (18)F-FDG, approximately. Mean standardized uptake value (SUV) in each lesion was measured at each time point and the increase rate of SUV (IR_SUV) was calculated. SUV and IR_SUV were compared among the 3 groups. In addition, to estimate differences in kinetic parameters for each group, kinetic analysis based on a 3-compartment model was performed. Our results showed SUV differed significantly at every time point among the 3 groups. IR_SUV between 2 and 3 h post-injection (IR_SUV (2-3)) differed significantly among the 3 groups, while both IR_SUV(1-3) and IR_SUV(1-2) were significantly higher in SCC than in WDA. In kinetic analyses, both K1 and k3 showed significant differences among the 3 groups, with highest values in SCC and lowest in WDA. In conclusion, (18)F-FDG-PET 3-point imaging and kinetic analysis enabled the differentiation of histological subtypes in lung cancer, arising from differences in glucose transporter density and enzymatic activity of hexokinase.
Hell J Nucl Med
PMID:Differentiation of histological subtypes in lung cancer with 18F-FDG-PET 3-point imaging and kinetic analysis. 2208 39

Stabilization of central carbohydrate metabolism plays a key role in plant stress response. Carbohydrates are substrate for numerous metabolic and stress-responsive reactions and have been shown to be involved in diverse signalling processes on a whole-plant level. Regulation of enzymatic sucrose synthesis and degradation is well-known to be central to many stress-related processes as it significantly impacts stress tolerance. Leaf sucrose metabolism involves sucrose cleavage by invertases and ATP-consuming resynthesis catalysed by hexokinase and sucrose phosphate synthase. These reactions establish a metabolic cycle. To study the physiological role of sucrose cycling, a kinetic model was developed to simulate dynamics of subcellular sugar concentrations in Arabidopsis thaliana under combined cold and high-light stress. Model simulation revealed that subcellular reprogramming of invertase-driven sucrose cleavage varies substantially between natural accessions of Arabidopsis which differ in their cold tolerance levels. A stress-induced shift of sucrose cleavage from the cytosol into the vacuole could only be observed for the tolerant accession while the susceptible accession increased the cytosolic proportion of sucrose cleavage. Under stress, reduction in vacuolar invertase activity significantly affected maximum quantum yield of photosystem II and CO2 assimilation rates. While wild-type plants circumvented a limitation of sucrose cleavage by increasing vacuolar invertase activity, mutant plants were not able to compensate their deficiency of vacuolar by cytosolic activity. Consequently, the capacity for cytosolic hexose generation was lower than for enzymatic hexose phosphorylation suggesting a role of vacuolar invertase activity in preventing a limitation in cytosolic hexose metabolism under stress. ENZYMES: Invertase, EC 3.2.1.26; Hexokinase, EC 2.7.1.1.
 ...
PMID:Vacuolar sucrose cleavage prevents limitation of cytosolic carbohydrate metabolism and stabilizes photosynthesis under abiotic stress. 3021 82


<< Previous 1 2 3