Search results for "Antiporters"

The Fumarate/Succinate Antiporter DcuB of Escherichia coli Is a Bifunctional Protein with Sites for Regulation of DcuS-dependent Gene Expression

2008

DcuB of Escherichia coli catalyzes C4-dicarboxylate/succinate antiport during growth by fumarate respiration. The expression of genes of fumarate respiration, including the genes for DcuB (dcuB) and fumarate reductase (frdABCD) is transcriptionally activated by C4-dicarboxylates via the DcuS-DcuR two-component system, comprising the sensor kinase DcuS, which contains a periplasmic sensing domain for C4-dicarboxylates. Deletion or inactivation of dcuB caused constitutive expression of DcuS-regulated genes in the absence of C4-dicarboxylates. The effect was specific for DcuB and not observed after inactivation of the homologous DcuA or the more distantly related DcuC transporter. Random and s…

Calcium signatures and signaling in cytosol and organelles of tobacco cells induced by plant defense elicitors

2011

Calcium signatures induced by two elicitors of plant defense reactions, namely cryptogein and oligogalacturonides, were monitored at the subcellular level, using apoaequorin-transformed Nicotiana tabacum var Xanthi cells, in which the apoaequorin calcium sensor was targeted either to cytosol, mitochondria or chloroplasts. Our study showed that both elicitors induced specific Ca2+ signatures in each compartment, with the most striking difference relying on duration. Common properties also emerged from the analysis of Ca2+ signatures: both elicitors induced a biphasic cytosolic [Ca2+] elevation together with a single mitochondrial [Ca2+] elevation concomitant with the first cytosolic [Ca2+] p…

Is ABA involved in tolerance responses to salinity by affecting cytoplasm ion homeostasis in rice cell lines?

2012

Abstract The ability of plant cells to maintain cytoplasm ion homeostasis under saline stress is among the main mechanisms involved in salt tolerance. To cope with excess Na + , cells extrude it from the cytoplasm, which requires expenditure of metabolic energy, provided by H + gradients generated by membrane-bound H + -pumps. ABA is well-known to be involved in physiological processes elicited or enhanced by stresses causing cell dehydration. In this work we studied the possible implication of this plant hormone in the control of salt-induced cellular mechanisms conducting to Na + extrusion from the cytoplasm. We used rice ( Oryza sativa L.) cell lines selected for their different toleranc…

De Novo Mutations in SLC25A24 Cause a Disorder Characterized by Early Aging, Bone Dysplasia, Characteristic Face, and Early Demise

2017

International audience; A series of simplex cases have been reported under various diagnoses sharing early aging, especially evident in congenitally decreased subcutaneous fat tissue and sparse hair, bone dysplasia of the skull and fingers, a distinctive facial gestalt, and prenatal and postnatal growth retardation. For historical reasons, we suggest naming the entity Fontaine syndrome. Exome sequencing of four unrelated affected individuals showed that all carried the de novo missense variant c.649C>T (p.Arg217Cys) or c.650G>A (p.Arg217His) in SLC25A24, a solute carrier 25 family member coding for calcium-binding mitochondrial carrier protein (SCaMC-1, also known as SLC25A24). SLC25A24 all…

Insulin-like growth factor 1 and sodium-lithium countertransport in essential hypertension and in hypertensive left ventricular hypertrophy

1993

The aim of this work was to study the insulin-like growth factor 1 (IGF1), a substance able to promote cell proliferation in vascular smooth muscle, in patients with mild-to-moderate hypertension and to analyse its relationship to sodium-lithium countertransport, a genetic marker of hypertension that is related to cardiovascular complications.We studied 32 hypertensive subjects, some with left ventricular hypertrophy, and 14 healthy subjects. Fasting plasma IGF1 was measured by means of a radioimmunoassay after octadecylsilica chromatography and Na(+)-Li+ countertransport was determined by the method of Canessa.Hypertensive patients had higher values of both IGF1 and Na(+)-Li+ countertransp…

Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR genes) two-component regulatory system.

1998

ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C 4 -dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previously yjdHG ) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR and dcuS genes caused the loss of C 4 -dicarboxylate-stimulated synthesis of fumarate reductase ( frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB ( dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C 4…

Bipartite regulation of different components of the MHC class I antigen-processing machinery during dendritic cell maturation

2001

Dendritic cells (DC) are professional antigen-presenting cells (APC) which proceed from immature to a mature stage during their final differentiation. Immature DC are highly effective in terms of antigen uptake and processing, whereas mature DC become potent immunostimulatory cells. Until now, the expression profiles of the major components of the MHC class I antigen-processing machinery (APM) during DC development have not been well characterized. In this study, the mRNA and protein expression levels of the IFN-gamma inducible proteasome subunits, of the proteasome activators PA28, and of key components required for peptide transport and MHC class I-peptide complex assembly have been evalu…

Cloning and functional analyses of the mouse tapasin promoter

2003

The expression of tapasin is critical for an optimized MHC class I assembly and stable MHC class I surface expression. Thus, impaired MHC class I antigen expression of tumors can be attributable to tapasin downregulation. In order to understand the molecular mechanisms of deficient tapasin expression, the mouse tapasin promoter region and its 5'-flanking sequences were characterized. The mouse tapasin promoter lacks the TATA box and its transcription is initiated at multiple sites within a 51-nucleotide stretch. Sequence analyses revealed transcription factor binding motifs for NF-kappaB, GATA, E2F, p300, AP1, SP1 and IRF-1/2. Detailed analysis of deletion mutants and elimination of transcr…

Bowel Dilation Diagnosed Prenatally.

2017

The CFTR associated protein CAP70 interacts with the apical Cl-/HCO3- exchanger DRA in rabbit small intestinal mucosa.

2005

DRA (down regulated in adenoma) is an intestinal anion exchanger, acting in parallel with NHE3 to facilitate ileal and colonic NaCl absorption. Furthermore it is involved in small intestinal bicarbonate secretion. Because DRA has a PDZ interaction motif, which may influence its properties, we searched for DRA-interacting PDZ adapter proteins in the small intestine. Using an overlay assay with the recombinant DRA C-terminus as a ligand, a 70 kDa protein was labeled, which was restricted to the brush border membrane in rabbit duodenal and ileal mucosa and was not detected in the colon. Destruction of the C-terminal PDZ interaction motif abolished this band, suggesting a specific protein-prote…