TREK-2, a new member of the mechanosensitive tandem-pore K+ channel family.

Recently, several mammalian K(+) channel subunits (TWIK, TREK-1, TRAAK, and TASK) possessing four transmembrane segments and two pore-forming domains have been identified. We report the cloning of a new member of this tandem-pore K(+) channel from a rat cerebellum cDNA library. It is a 538-amino acid protein and shares 65% amino acid sequence identity with TREK-1.

TASK-3, a new member of the tandem pore K(+) channel family.

We have isolated from the rat cerebellum cDNA library a complementary DNA encoding a new member of the tandem pore K(+) channel family. Its amino acid sequence shares 54% identity with that of TASK-1, but less than 30% with those of TASK-2 and other tandem pore K(+) channels (TWIK, TREK, TRAAK). Therefore, the new clone was named TASK-3.

TBAK-1 and TASK-1, two-pore K(+) channel subunits: kinetic properties and expression in rat heart.

A mammalian K(+) channel subunit (TBAK-1/TASK-1) containing two pore domains and four transmembrane segments and whose mRNA is highly expressed in the heart has been cloned recently. TBAK-1 and TASK-1 are identical except for the additional nine amino acids in the NH(2) terminus of TBAK-1. We examined their kinetic properties, pH sensitivity, and regional cardiac mRNA expression and determined whether a native cardiac K(+) channel with similar kinetic properties was present.

Interaction of cyclophilin and cyclosporins monitored by affinity capillary electrophoresis.

The affinity capillary electrophoretic separation of the complex of the enzyme cyclophilin (Cyp) with the immunosuppressive drug cyclosporin A (CsA) from uncomplexed Cyp and CsA in phosphate buffer (pH 8) under non-denaturing conditions by equilibrium-mixture analysis is reported. Using a new approach combining mobility-shift analysis and electrophoretically mediated microanalysis the binding constant of rhCyp18 to CsA and derivatives was estimated.

Kinetics of alpha-amylase secretion in Aspergillus oryzae.

Pulse and pulse-chase experiments have been performed to study L-[(35)S] methionine incorporation and protein secretion kinetics in Aspergillus oryzae. Pulse experiments confirmed the mechanism of methionine uptake reported previously for Penicillium chrysogenum (Benko et al., 1967).

Modulation of rat atrial G protein-coupled K+ channel function by phospholipids.

1. G protein-gated K+ channels (KACh channels) in the heart and brain are activated by the betagamma subunit of inhibitory G protein. Phosphatidylinositol-4,5-bisphosphate (PIP2) has recently been reported to directly activate KACh channels (GIRK) expressed in oocytes, as well as to support activation by the betagamma subunit in the presence of Na+.

Purification and characterization of GTP cyclohydrolase I from Streptomyces tubercidicus, a producer of tubercidin.

GTP cyclohydrolase I catalyzing the first reaction in the biosynthesis of pterin moiety of folic acid in bacteria, was purified from Streptomyces tubercidicus by at least 203-fold with a yield of 32% to apparent homogeneity, using ammonium sulfate fractionation, DEAE-cellulose, Sepharose CL-6B, and hydroxylapatite column chromatography. The molecular weight of the native enzyme was estimated to be 230,000 daltons by gel permeation chromatography. The purified enzyme gave a single band on sodium dodesyl sulfate-polyacrylamide gel electrophoresis and its molecular weight was apparently 58,000 daltons.

Leishmania major parasites express cyclophilin isoforms with an unusual interaction with calcineurin.

The immunosuppressive effects of the fungal metabolite cyclosporin A (CsA) are mediated primarily by binding to cyclophilins (Cyps). The resulting CsA-Cyp complex inhibits the Ca2+-regulated protein phosphatase calcineurin and down-regulates signal transduction events. Previously we reported that CsA is a potent inhibitor of infections transmitted by the human pathogenic protozoan parasite Leishmania major in vitro and in vivo, but does not effect the extracellular growth of L.

Molecular analysis of rifampin-resistant Mycobacterium tuberculosis isolated from Korea by polymerase chain reaction-single strand conformation polymorphism sequence analysis.

Objective: To assess the molecular mechanism of rifampin (RMP) resistance in clinical strains of Mycobacterium tuberculosis.

Design: The molecular nature of a part of the rpoB gene in 77 M. tuberculosis clinical strains isolated in Korea was analyzed using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and PCR-sequence analysis.

Recognition of protein substrates by the prolyl isomerase trigger factor is independent of proline residues.

The trigger factor is associated with bacterial ribosomes and catalyzes proline-limited protein folding reactions. Its folding activity is very high and conserved in evolution, as shown for the homologous enzymes from Escherichia coli and Mycoplasma genitalium. The folding protein substrate (a variant of ribonuclease T1) binds with high affinity to the trigger factors, and permanently unfolded proteins are strong, competitive inhibitors.

Delayed rectifier potassium currents induced in activated rat microglia set the resting membrane potential.

The delayed rectifying outward K+ (IK) current was measured in lipopolysaccharide (LPS)-activated cultured rat microglial cells by using whole-cell patch clamp method. The current showed 'window current' where channels were available for activation but never fully inactivated. At near resting membrane potential some part of the current was able to be activated by depolarization.

Modulation of transcription factor NF-kappaB by enantiomers of the nonsteroidal drug ibuprofen.

1. The nonsteroidal drug ibuprofen exists as an R(-)- and S(+)-enantiomer. Only the S(+)-enantiomer is an effective cyclo-oxygenase inhibitor, while the R(-)-enantiomer is inactive in this respect.

Elevated serum cyclophilin levels in patients with severe sepsis.

Several cytokines are considered to be important mediators in the pathophysiology of sepsis. Cyclophilins (Cyps), the main binding proteins for the immunosuppressive drug cyclosporine A, have been suggested to function as cytokines. This study was conducted to determine (i) if serum Cyp levels were elevated in critically ill patients suffering from either sepsis or other life-threatening diseases and (ii) if so, whether there was an association between Cyp levels and a certain diagnosis and/or outcome.

Interval cancers and cancers in non-attenders in the Ostergötland Mammographic Screening Programme. Duration between screening and diagnosis, S-phase fraction and distant recurrence.

The study was based on a population mammographic screening programme for women aged 40-74 years. Metastatic potential was analysed in 843 invasive breast cancers with regard to mode of detection and a number of prognostic factors. There was a higher metastatic capacity in clinically detected cases, but multivariate analyses showed that neither the mode of detection (hazard rate ratio of distant recurrence RR = 1.

A novel threonine --> proline mutation at the end of 2B rod domain in the keratin 2e chain in ichthyosis bullosa of Siemens.

We report a novel mutation in a case of ichthyosis bullosa of Siemens that results in a threonine --> proline substitution in a novel location, codon 485 in a highly conserved residue position of the IATYRKLLEGE consensus motif at the end of the 2B rod domain segment of the keratin 2e chain. The disease phenotype is consistent with the inappropriate substitution of a proline near the end of the rod domain, because it lies near the predicted molecular overlap region of coiled-coil molecules, which is critical for the maintenance of the structural integrity of keratin intermediate filaments.

Fit for life? Evolution of chaperones and folding catalysts parallels the development of complex organisms.

No Abstract Available

Host-cell cyclophilin is important for the intracellular replication of Leishmania major.

The antiparasitic effects of cyclosporin A were examined in leishmanial infection by analysing the role of CsA-binding proteins (cyclophilins) in the host-parasite interaction. We hypothesized that the leishmanicidal effects of CsA on Leishmania major infected macrophages might be mediated through a cyclophilin of either the parasite or the host cell. Two cyclophilins (20 and 22 kDa) were purified from L.

Molecular cloning and expression of a 2-arylpropionyl-coenzyme A epimerase: a key enzyme in the inversion metabolism of ibuprofen.

The 2-arylpropionic acid derivatives, including ibuprofen, are the most widely used anti-inflammatory analgesic cyclooxygenase inhibitors. The (-)-R-enantiomer, which is inactive in terms of cyclooxygenase inhibition, is epimerized in vivo via the 2-arylpropionyl-coenzyme A (CoA) epimerase to the cyclooxygenase-inhibiting (+)-S-enantiomer. The molecular biology of the epimerization pathway is largely unknown.

Modulation of large conductance Ca2+-activated K+ channel by Galphah (transglutaminase II) in the vascular smooth muscle cell.

Among G-proteins, Gh is unique in structural differences in the GTP-binding domain and possessing transglutaminase activity. We have studied the role of G protein in modulation of large conductance Ca2+-activated K+ (Maxi-K+) channel by the inside-out mode of patch clamp in smooth muscle cells from superior mesenteric artery of the rabbit. When the non-hydrolyzable GTP analogue, GTPgammaS, was applied, the channel activity was increased about 2.

Biapenem versus imipenem/cilastatin in the treatment of complicated intra-abdominal infections: report from a Swedish Study Group.

118 patients with complicated intra-abdominal infections participated in an open randomized comparative multicenter trial in order to compare the clinical and microbiological efficacy and safety of biapenem with imipenem/cilastatin (Tienam). 31 men and 27 women (mean age 52.3 years) were enrolled in the biapenem group, and 43 men and 17 women (mean age 52.

2-Arylpropionyl-CoA epimerase: partial peptide sequences and tissue localization.

The R-enantiomers of 2-arylpropionic acids (2-APAs) such as ibuprofen (IBU) exhibit the phenomenon of species- and substrate-dependent metabolic chiral inversion. Only R-enantiomers are activated to acyl-CoA-thioesters by an acyl-CoA-synthetase via an adenylate intermediate. The acyl-CoA-thioesters are substrates for an epimerase, which is responsible for chiral inversion.