IAPs, RINGs and ubiquitylation.
ABSTRACT The inhibitor of apoptosis (IAP) proteins all contain one or more baculoviral IAP repeat motifs, through which they interact with various other proteins. Many IAPs also have another zinc-binding motif, the RING domain, which can recruit E2 ubiquitin-conjugating enzymes and catalyse the transfer of ubiquitin onto target proteins. The number of targets of IAP-mediated ubiquitylation is increasing and recent results indicate that outcomes following ubiquitylation are tantalizingly complex. As well as regulating other proteins, the IAPs themselves are controlled by ubiquitin-mediated degradation.
- SourceAvailable from: Vassiliki Nikoletopoulou[Show abstract] [Hide abstract]
ABSTRACT: The concept that target tissues determine the survival of neurons has inspired much of the thinking on neuronal development in vertebrates, not least because it is supported by decades of research on nerve growth factor (NGF) in the peripheral nervous system (PNS). Recent discoveries now help to understand why only some developing neurons selectively depend on NGF. They also indicate that the survival of most neurons in the central nervous system (CNS) is not simply regulated by single growth factors like in the PNS. Additionally, components of the cell death machinery have begun to be recognized as regulators of selective axonal degeneration and synaptic function, thus playing a critical role in wiring up the nervous system.The Journal of Cell Biology 11/2013; 203(3):385-93. DOI:10.1083/jcb.201306136 · 9.69 Impact Factor
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ABSTRACT: Innate immunity is essential for insects to survive infectious pathogens. In baculovirus-infected lepidopteran cells, apoptosis and global protein synthesis shutdown are major mechanisms of intracellular innate immunity that inhibit viral replication. In contrast, baculoviruses have evolved diverse genes and mechanisms to counter the antiviral immunity activated in infected cells. In this review, we summarize the current knowledge of the cellular antiviral pathways and the baculovirus genes that modulate antiviral immunity. The studies highlighted illustrate a high degree of diversity in both the cellular responses against viral infections and viral responses against intracellular antiviral immunity, providing an important basis of further studies in this field.Virology 01/2013; 435(1):1-13. DOI:10.1016/j.virol.2012.10.016 · 3.28 Impact Factor
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ABSTRACT: Although the functions of a few effector proteins produced by bacterial and oomycete plant pathogens have been elucidated in recent years, information for the vast majority of pathogen effectors is still lacking, particularly for those of plant-pathogenic fungi. Here, we show that the avirulence effector AvrPiz-t from the rice blast fungus Magnaporthe oryzae preferentially accumulates in the specialized structure called the biotrophic interfacial complex and is then translocated into rice (Oryza sativa) cells. Ectopic expression of AvrPiz-t in transgenic rice suppresses the flg22- and chitin-induced generation of reactive oxygen species (ROS) and enhances susceptibility to M. oryzae, indicating that AvrPiz-t functions to suppress pathogen-associated molecular pattern (PAMP)-triggered immunity in rice. Interaction assays show that AvrPiz-t suppresses the ubiquitin ligase activity of the rice RING E3 ubiquitin ligase APIP6 and that, in return, APIP6 ubiquitinates AvrPiz-t in vitro. Interestingly, agroinfection assays reveal that AvrPiz-t and AvrPiz-t Interacting Protein 6 (APIP6) are both degraded when coexpressed in Nicotiana benthamiana. Silencing of APIP6 in transgenic rice leads to a significant reduction of flg22-induced ROS generation, suppression of defense-related gene expression, and enhanced susceptibility of rice plants to M. oryzae. Taken together, our results reveal a mechanism in which a fungal effector targets the host ubiquitin proteasome system for the suppression of PAMP-triggered immunity in plants.The Plant Cell 11/2012; DOI:10.1105/tpc.112.105429 · 9.58 Impact Factor