71 research outputs found
The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast
The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al
Functional Expression of Human Adenine Nucleotide Translocase 4 in Saccharomyces Cerevisiae
The adenine nucleotide translocase (ANT) mediates the exchange of ADP and ATP across the inner mitochondrial membrane. The human genome encodes multiple ANT isoforms that are expressed in a tissue-specific manner. Recently a novel germ cell-specific member of the ANT family, ANT4 (SLC25A31) was identified. Although it is known that targeted depletion of ANT4 in mice resulted in male infertility, the functional biochemical differences between ANT4 and other somatic ANT isoforms remain undetermined. To gain insight into ANT4, we expressed human ANT4 (hANT4) in yeast mitochondria. Unlike the somatic ANT proteins, expression of hANT4 failed to complement an AAC-deficient yeast strain for growth on media requiring mitochondrial respiration. Moreover, overexpression of hANT4 from a multi-copy plasmid interfered with optimal yeast growth. However, mutation of specific amino acids of hANT4 improved yeast mitochondrial expression and supported growth of the AAC-deficient yeast on non-fermentable carbon sources. The mutations affected amino acids predicted to interact with phospholipids, suggesting the importance of lipid interactions for function of this protein. Each mutant hANT4 and the somatic hANTs exhibited similar ADP/ATP exchange kinetics. These data define common and distinct biochemical characteristics of ANT4 in comparison to ANT1, 2 and 3 providing a basis for study of its unique adaptation to germ cells
Rate and duration of hospitalisation for acute pulmonary embolism in the real-world clinical practice of different countries : Analysis from the RIETE registry
publishersversionPeer reviewe
Idraparinux: review of its clinical efficacy and safety for prevention andtreatment of thromboembolic disorders.
1. Expert Opin Investig Drugs. 2008 May;17(5):773-7.
Idraparinux: review of its clinical efficacy and safety for prevention and
treatment of thromboembolic disorders.
Prandoni P, Tormene D, Perlati M, Brandolin B, Spiezia L.
Department of Medical and Surgical Sciences, Thromboembolism Unit, University of
Padua, 35128 - Padua, Italy. [email protected]
BACKGROUND: Idraparinux is a synthetic pentasaccharide that binds to antithrombin
with high affinity. In view of its long half-life, it is suitable for once-a-week
administration.
OBJECTIVE: To review the evidence favoring the use of idraparinux for the acute
and long-term treatment of patients with venous thromboembolism (VTE) and for the
prevention of thromboembolic events in patients with atrial fibrillation (AF).
METHODS: All preclinical and clinical studies carried out with the use of
idraparinux were sought through electronic searches of MEDLINE from January 1,
1999 up to December 31, 2007.
RESULTS: The administration of idraparinux in subcutaneous fixed doses of 2.5 mg
once weekly was found to be as effective and safe as conventional antithrombotic
therapy in the initial treatment of patients with deep vein thrombosis, but less
effective than standard therapy in the initial treatment of patients with primary
pulmonary embolism. During a 6-month extension of thromboprophylaxis, idraparinux
was effective in preventing recurrent VTE but was associated with an increased
risk of bleeding versus placebo. Finally, in patients with AF the long-term
treatment with idraparinux was as effective as vitamin K antagonists, but caused
more bleeding.
CONCLUSIONS: In its current formulation, idraparinux can be recommended only for
the initial treatment of patients with deep vein thrombosis. The bioequipotency
of a biotinylated version of idraparinux (idrabiotaparinux), whose effects can be
reversed by a neutralizing agent (avidin), is under investigation in the
treatment of VTE at present, as is the use of lower doses in patients with AF.
PMID: 18447601 [PubMed - indexed for MEDLINE
A phosphatidylserine-binding site in the cytosolic fragment of clostridium sordellii lethal toxin facilitates glucosylation of membrane-bound Rac and is required for cytotoxicity.
Large clostridial toxins glucosylate some small G proteins on a threonine residue, thereby preventing their interactions with effector molecules and regulators. We show that the glucosyltransferase domain of lethal toxin from Clostridium sordellii (LT(cyt); amino acids 1-546), which is released into the cytosol during cell infection, binds preferentially to liposomes containing phosphatidylserine as compared with other anionic lipids. The binding of LT(cyt) to phosphatidylserine increases by two orders of magnitude the rate of glucosylation of liposome-bound geranyl-geranylated Rac-GDP. Limited proteolysis and deletion studies show that the binding site for phosphatidylserine lies within the first 18 N-terminal residues of LT(cyt). Deletion of these residues abolishes the effect of phosphatidylserine on the activity of LT(cyt) on liposome-bound geranyl-geranylated Rac-GDP and prevents the morphological effects induced by LT(cyt) microinjection into various cells, but it does not affect the intrinsic activity of LT(cyt) on non-geranyl-geranylated Rac-GDP in solution. We conclude that the avidity of LT(cyt) for phosphatidylserine facilitates its targeting to the cytosolic leaflet of cell membranes and, notably, the plasma membrane, where this anionic lipid is abundant and where several targets of lethal toxin resid
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