@article{KatoLuRapaportetal.2013, author = {Kato, Hiroki and Lu, Qiping and Rapaport, Doron and Kozjak-Pavlovic, Vera}, title = {Tom70 Is Essential for PINK1 Import into Mitochondria}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0058435}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131061}, pages = {e58435}, year = {2013}, abstract = {PTEN induced kinase 1 (PINK1) is a serine/threonine kinase in the outer membrane of mitochondria (OMM), and known as a responsible gene of Parkinson's disease (PD). The precursor of PINK1 is synthesized in the cytosol and then imported into the mitochondria via the translocase of the OMM (TOM) complex. However, a large part of PINK1 import mechanism remains unclear. In this study, we examined using cell-free system the mechanism by which PINK1 is targeted to and assembled into mitochondria. Surprisingly, the main component of the import channel, Tom40 was not necessary for PINK1 import. Furthermore, we revealed that the import receptor Tom70 is essential for PINK1 import. In addition, we observed that although PINK1 has predicted mitochondrial targeting signal, it was not processed by the mitochondrial processing peptidase. Thus, our results suggest that PINK1 is imported into mitochondria by a unique pathway that is independent of the TOM core complex but crucially depends on the import receptor Tom70.}, language = {en} } @article{ZhaoZhangBhuripanyoetal.2013, author = {Zhao, Bo and Zhang, Keya and Bhuripanyo, Karan and Choi, Chan Hee J. and Villhauer, Eric B. and Li, Heng and Zheng, Ning and Kiyokawa, Hiroaki and Schindelin, Hermann and Yin, Jun}, title = {Profiling the Cross Reactivity of Ubiquitin with the Nedd8 Activating Enzyme by Phage Display}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {e70312}, issn = {1932-6203}, doi = {10.1371/journal.pone.0070312}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128479}, year = {2013}, abstract = {The C-terminal peptides of ubiquitin (UB) and UB-like proteins (UBLs) play a key role in their recognition by the specific activating enzymes (E1s) to launch their transfer through the respective enzymatic cascades thus modifying cellular proteins. UB and Nedd8, a UBL regulating the activity of cullin-RING UB ligases, only differ by one residue at their C-termini; yet each has its specific E1 for the activation reaction. It has been reported recently that UAE can cross react with Nedd8 to enable its passage through the UB transfer cascade for protein neddylation. To elucidate differences in UB recognition by UAE and NAE, we carried out phage selection of a UB library with randomized C-terminal sequences based on the catalytic formation of UB similar to NAE thioester conjugates. Our results confirmed the previous finding that residue 72 of UB plays a "gate-keeping" role in E1 selectivity. We also found that diverse sequences flanking residue 72 at the UB C-terminus can be accommodated by NAE for activation. Furthermore heptameric peptides derived from the C-terminal sequences of UB variants selected for NAE activation can function as mimics of Nedd8 to form thioester conjugates with NAE and the downstream E2 enzyme Ubc12 in the Nedd8 transfer cascade. Once the peptides are charged onto the cascade enzymes, the full-length Nedd8 protein is effectively blocked from passing through the cascade for the critical modification of cullin. We have thus identified a new class of inhibitors of protein neddylation based on the profiles of the UB C-terminal sequences recognized by NAE.}, language = {en} } @article{GeyerChalmersMacKintoshetal.2013, author = {Geyer, Kathrin K. and Chalmers, Iain W. and MacKintosh, Neil and Hirst, Julie E. and Geoghegan, Rory and Badets, Mathieu and Brophy, Peter M. and Brehm, Klaus and Hoffmann, Karl F.}, title = {Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes}, series = {BMC Genomics}, volume = {14}, journal = {BMC Genomics}, number = {462}, issn = {1471-2164}, doi = {10.1186/1471-2164-14-462}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-121892}, year = {2013}, abstract = {Background: The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. Results: Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and 'Turbellaria') contain methylated cytosines within their genome compartments. Conclusions: Collectively, these findings provide the first direct evidence for a functionally conserved and enzymatically active DNA methylation system throughout the Platyhelminthes. Defining how this epigenetic feature shapes phenotypic diversity and development within the phylum represents an exciting new area of metazoan biology.}, language = {en} }