Publications
Wanted Plasmodium falciparum, dead or alive
June 23, 2015
In this article, mechanisms of cell death in unicellular parasites are discussed, focussing on “programmed cell death” in Plasmodium.
Yeast as a tool to explore cathepsin D function
June 11, 2015
Cathepsin D has garnered increased attention in recent years, mainly since it has been associated with several human pathologies. This review summarizes how cathepsin D can have both anti- and pro-survival functions depending on its proteolytic activity, cellular context and stress stimulus.
Toxoplasma control of host apoptosis: the art of not biting too hard the hand that feeds you
May 30, 2015
Toxoplasma gondii is an obligate intracellular parasite that is able to infect a multitude of different vertebrate hosts and can survive in virtually any nucleated cell. Here, the authors discuss the article "Toxoplasma gondii inhibits cytochrome c-induced caspase activation in its host cell by interference with holo-apoptosome assembly" by Graumann et al. (2015, Microbial Cell).
A safety catch for ornithine decarboxylase degradation
May 27, 2015
Feedback inhibition is a common mechanism to adjust the activity of an enzyme in accordance with the abundance of a product. This article comments on the study "Polyamines directly promote antizyme-mediated degradation of ornithine decarboxylase by the proteasome" by Beenukumar et al. (2015), Microbial Cell.
Coordinate responses to alkaline pH stress in budding yeast
May 22, 2015
This review summarizes the modulation of a substantial number of signaling pathways whose participate in the alkaline response in yeast. These regulatory inputs involve not only the conserved Rim101/PacC pathway, but also the calcium-activated phosphatase calcineurin, the Wsc1-Pkc1-Slt2 MAP kinase, the Snf1 and PKA kinases and oxidative stress-response pathways.
Handcuffs for bacteria – NDP52 orchestrates xenophagy of intracellular Salmonella
May 21, 2015
This microreview discusses the article "Autophagy Receptor NDP52 Regulates Pathogen-Containing Autophagosome Maturation" by Verlhac et al. (2015), Cell Host Microbe.
Polyamines directly promote antizyme-mediated degradation of ornithine decarboxylase by the proteasome
May 20, 2015
Ornithine decarboxylase (ODC), a ubiquitin-independent substrate of the proteasome, is a homodimeric protein with a rate-limiting function in polyamine biosynthesis. Polyamines regulate ODC levels by a feedback mechanism mediated by ODC antizyme (OAZ). Higher cellular polyamine levels trigger the synthesis of OAZ and also inhibit its ubiquitin-dependent proteasomal degradation. OAZ binds ODC monomers and targets them to the proteasome. Here, we report that polyamines, aside from their role in the control of OAZ synthesis and stability, directly enhance OAZ-mediated ODC degradation by the proteasome. Using a stable mutant of OAZ, we show that polyamines promote ODC degradation in Saccharomyces cerevisiae cells even when OAZ levels are not changed. Furthermore, polyamines stimulated the in vitro degradation of ODC by the...
Toxoplasma gondii inhibits cytochrome c-induced caspase activation in its host cell by interference with holo-apoptosome assembly
May 4, 2015
Inhibition of programmed cell death pathways of mammalian cells often facilitates the sustained survival of intracellular microorganisms. The apicomplexan parasite Toxoplasma gondii is a master regulator of host cell apoptotic pathways. Here, we have characterized a novel anti-apoptotic activity of T. gondii. Using a cell-free cytosolic extract model, we show that T. gondii interferes with the activities of caspase 9 and caspase 3/7 which have been induced by exogenous cytochrome c and dATP. Proteolytic cleavage of caspases 9 and 3 is also diminished suggesting inhibition of holo-apoptosome function. Parasite infection of Jurkat T cells and subsequent triggering of apoptosome formation by exogenous cytochrome c in vitro and in vivo indicated that...
Understanding grapevine-microbiome interactions: implications for viticulture industry
May 4, 2015
This microreview discusses the article "The soil microbiome influences grapevine-associated microbiota" by Zarraonaindia et al. (2015), MBio, which reports that the grapevine-associated microbiota depends on the soil microbiome.