Endonuclease G (EndoG) is located in mitochondria yet translocates into the nucleus of apoptotic cells during human degenerative diseases. Nonetheless, a direct involvement of EndoG in cell-death execution remains equivocal, and the mechanism for mitochondrio-nuclear translocation is not known. Here, we show that the yeast homolog of EndoG (Nuc1p) can efficiently trigger apoptotic cell death when excluded from mitochondria. Nuc1p induces apoptosis in yeast independently of metacaspase or of apoptosis inducing factor. Instead, the permeability transition pore, karyopherin Kap123p, and histone H2B interact with Nuc1p and are required for cell death upon Nuc1p overexpression, suggesting a pathway in which mitochondrial pore opening, nuclear import, and chromatin association are successively involved in EndoG-mediated death. Deletion of NUC1 diminishes apoptotic death when mitochondrial respiration is increased but enhances necrotic death when oxidative phosphorylation is repressed, pointing to dual--lethal and vital--roles for EndoG.

Thromboxane (TX) A 2 , a cyclooxygenase-derived mediator involved in allergic responses, is rapidly converted in vivo to a stable metabolite, 11-dehydro-TXB 2 , which is considered to be biologically inactive. In this study, we found that 11-dehydro-TXB 2 , but not the TXA 2 analogue U46,619 or TXB 2 , activated eosinophils and basophils, as assayed by flow cytometric shape change. 11-Dehydro-TXB 2 was also chemotactic for eosinophils but did not induce, nor inhibit, platelet aggregation. Chemoattractant receptor-homologous molecule expressed on TH2 cells (CRTH2) is an important chemoattractant receptor expressed by eosinophils, basophils, and TH2 lymphocytes, and prostaglandin (PG)D 2 has been shown to be its principal ligand. 11-Dehydro-TXB 2 induced calcium flux mainly from intracellular stores in eosinophils, and this response was desensitized after stimulation with PGD 2 but not other eosinophil chemoattractants. Shape change responses of eosinophils and basophils to 11-dehydro-TXB 2 were inhibited by the thromboxane (TP)/CRTH2 receptor antagonist ramatroban, but not the selective TP antagonist SQ29,548, and were insensitive to pertussis toxin. The phospholipase C inhibitor U73,122 attenuated both 11-dehydro-TXB 2 -and PGD 2 -induced shape change. 11-Dehydro-TXB 2 also induced the chemotaxis of BaF/3 cells transfected with hCRTH2 but not naive BaF/3 cells. At a threshold concentration, 11-dehydro-TXB 2 had no antagonistic effect on CRTH2-mediated responses as induced by PGD2. These data show that 11-dehydro-TXB 2 is a full agonist of the CRTH2 receptor and hence might cause CRTH2 activation in cellular contexts where PGD-synthase is not present. Given its production in the allergic lung, antagonism of the 11-dehydro-TXB 2 /CRTH2axis may be of therapeutic relevance.

Graphical abstractA series of new 1-methyl-2-alkenyl-4(1H)-quinolones lacking carboxyl, fluorine and piperazinyl at position-3, -6 and -7, respectively, have been synthesized and tested in vitro against fast growing species of mycobacteria.

Adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) are key enzymes involved in intracellular degradation of triacylglycerols. It was the aim of this study to elucidate how the deficiency in one of these proteins affects the residual lipolytic proteome in adipose tissue. For this purpose, we compared the lipase patters of brown and white adipose tissue from ATGL (؊/؊) and HSL (؊/؊) mice using differential activity-based gel electrophoresis. This method is based on activity-recognition probes possessing the same substrate analogous structure but carrying different fluorophores for specific detection of the enzyme patterns of two different tissues in one electrophoresis gel. We found that ATGL-deficiency in brown adipose tissue had a profound effect on the expression levels of other lipolytic and esterolytic enzymes in this tissue, whereas HSL-deficiency hardly showed any effect in brown adipose tissue. Neither ATGL-nor HSL-deficiency greatly influenced the lipase patterns in white adipose tissue. Enzyme activities of mouse tissues on acylglycerol substrates were analyzed as well, showing that ATGL-and HSL-deficiencies can be compensated for at least in part by other enzymes. The proteins that responded to ATGL-deficiency in brown adipose tissue were overexpressed and their activities on acylglycerols were analyzed. Among these enzymes, Es1, Es10, and Es31-like represent lipase candidates as they catalyze the hydrolysis of long-chain acylglycerols. Molecular & Cellular Proteomics 11: 10.1074/mcp.M111.015743, 1777-1789, 2012.Excess lipids are stored as intracellular triacylglycerol and steryl ester deposits in animals, plant seeds, and fungi. In mammals adipose tissue is the body's largest storage organ for triacylglycerols (TAG) 1 as the primary source of energy during periods of starvation and increased energy demand. Two types of adipose tissue, namely brown (BAT) and white (WAT) adipose tissue exist in mammals, localizing to anatomically distinct areas. BAT and WAT differ in almost all their structural and functional features. Whereas BAT develops prenatally, WAT is subject to maturation postnatally. The different appearance of brown and white adipose tissue is caused by differences in lipid content and the abundance of mitochondria in the constituent adipocytes. Brown fat cells contain several small multilocular lipid droplets and a high number of large mitochondria with numerous cristae. In addition, BAT is highly vascularized and highly innervated by the sympathetic nervous system. In contrast, white adipocytes, usually contain one major unilocular lipid droplet that fills most of the cytoplasm leaving space for only few mitochondria (1-3). WAT accumulates excess energy as triacylglycerols, whereas BAT dissipates energy through adaptive thermogenesis. The thermogenic activity of BAT is caused by the expression of one protein unique in brown adipocytes, the uncoupling protein 1 (UCP1). This polypeptide is a facultative proton transporter and localizes to the inner mitochondrial membrane. I...

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