Specific Rab GTPase-activating proteins define the Shiga toxin and epidermal growth factor uptake pathways

Rab family guanosine triphosphatases (GTPases) together with their regulators define specific pathways of membrane traffic within eukaryotic cells. In this study, we have investigated which Rab GTPase-activating proteins (GAPs) can interfere with the trafficking of Shiga toxin from the cell surface to the Golgi apparatus and studied transport of the epidermal growth factor (EGF) from the cell surface to endosomes. This screen identifies 6 (EVI5, RN-tre/USP6NL, TBC1D10A–C, and TBC1D17) of 39 predicted human Rab GAPs as specific regulators of Shiga toxin but not EGF uptake. We show that Rab43 is the target of RN-tre and is required for Shiga toxin uptake. In contrast, RabGAP-5, a Rab5 GAP, was unique among the GAPs tested and reduced the uptake of EGF but not Shiga toxin. These results suggest that Shiga toxin trafficking to the Golgi is a multistep process controlled by several Rab GAPs and their target Rabs and that this process is discrete from ligand-induced EGF receptor trafficking

Construction of a Plasmodium falciparum Rab-interactome identifies CK1 and PKA as Rab-effector kinases in malaria parasites

Background information The pathology causing stages of the human malaria parasite Plasmodium falciparum reside within red blood cells that are devoid of any regulated transport system. The parasite, therefore, is entirely responsible for mediating vesicular transport within itself and in the infected erythrocyte cytoplasm, and it does so in part via its family of 11 Rab GTPases. Putative functions have been ascribed to Plasmodium Rabs due to their homology with Rabs of yeast, particularly with Saccharomyces that has an equivalent number of rab/ypt genes and where analyses of Ypt function is well characterized. Results Rabs are important regulators of vesicular traffic due to their capacity to recruit specific effectors. In order to identify P. falciparum Rab (PfRab) effectors, we first built a Ypt-interactome by exploiting genetic and physical binding data available at the Saccharomyces genome database (SGD). We then constructed a PfRab-interactome using putative parasite Rab-effectors identified by homology to Ypt-effectors. We demonstrate its potential by wet-bench testing three predictions; that casein kinase-1 (PfCK1) is a specific Rab5B interacting protein and that the catalytic subunit of cAMP-dependent protein kinase A (PfPKA-C) is a PfRab5A and PfRab7 effector. Conclusions The establishment of a shared set of physical Ypt/PfRab-effector proteins sheds light on a core set Plasmodium Rab-interactants shared with yeast. The PfRab-interactome should benefit vesicular trafficking studies in malaria parasites. The recruitment of PfCK1 to PfRab5B+ and PfPKA-C to PfRab5A+ and PfRab7+ vesicles, respectively, suggests that PfRab-recruited kinases potentially play a role in early and late endosome function in malaria parasites

What did the Royal Almoner do in Britain and Ireland, c.1450-1700?

The late medieval and early modern royal almoner for England and Wales was an important figure, a senior cleric best documented as a court preacher who was the crown’s religious and moral face; prominent holders included Wolsey and Lancelot Andrewes. The article begins by looking at the almoner’s appointment and functions at court, but it is mostly devoted to his interactions with Tudor and Stuart society at large. Indeed he had many public roles that are poorly understood. These included arbitrating, mediating, and directing the distribution of the forfeited goods of suicides found felo de se by coroners’ inquests, granted to successive almoners by the crown. The article looks at the almoner’s operations both in courts such as Star Chamber and outside them. It argues that he sought to create or repair communal bonds when survivors of suicide denied their obligations. Exploring what he did to re-establish charity between neighbours, his role as a benevolent giver, and the underlying religious imperatives that directed his actions, the article illuminates central issues of lordship, law and community in a period of profound social, legal, religious and political change. Focusing mainly on England, it also uncovers the significantly different roles of the separate royal almoners of Ireland and Scotland.PostprintPeer reviewe

Custom in context : Medieval and Early Modern Scotland and England

Studying custom and its context gives unique insights into relations of property, production and law in a society. The first part of the article discusses meaning in Scotland, focusing on ‘custom as normative practice, custom as unwritten law, and custom in opposition to law’. The second seeks to demonstrate (using evidence focusing principally on landholding) that custom as legal currency was more restricted for Scots than English. The third sets out the implications for continuity of landholding and for agrarian change in the Highlands of Scotland, an area where custom might be thought strong. The fourth deals with the differential legal development of Scotland and England between the twelfth and eighteenth centuries and its effects on social and tenurial relationships. A final section suggests why custom mattered more as a resource to the English, the domains in which it was important to Scots and the implications for understanding the comparative development of the two societies since the Middle Ages.PostprintPeer reviewe

RAB family gene expression in breast cancer cells under influence of paclitaxel

The aim of this study was to investigate the role of paclitaxel on RAB family of genes in primary breast cancer cell lines. The cancer breast cells obtained from 40 women during mastectomy were used to address this issue. The group included patients with intraductal breast cancer - lesions in I or II advancement level by TNM classification and G1-G2 by Bloom classification. (tumor dimensions up to 2.0 cm without metastases to lymph nodes). Cytostatic drugs before surgery were not administered to these patients. The cultures were conducted in 25 cm^2^ plastic containers at RPMI medium with addiction of 10% fetal bovine serum (FBS) at the standard conditions. After reaching concentration levels of 10 000/ml of the cells, the cultures were treated with 60 ng/ml and 300 ng/ml doses of paclitaxel. The concentrations were calculated in relation to therapeutic doses of paclitaxel, applied in polytherapy in patients with breast cancer. The cell cultures untreated for cytostatic were used as a control group. Analysis was conducted for RAB family of genes: RAB3D, RAB5B, RAB5C, RAB7, RAB7L1, RAB9P1, RAB10. RAB11A, RAB311B, RAB13, RAB18, RAB22A, RAB23, RAB26, RAB27A, RAB27B, RAB28, RAB30, RAB31, RAB33A, RAB3D6, RAB 38, RABL2B Total RNA was extracted from the harvest control group and the treated cells, and this was followed by cDNA synthesis, which was used for hybridization assays using arrays. A lower dose of paclitaxel (60 ng/ml) treatment resulted in an increase (2-4 fold- statistically significant), whereas a higher dose (300 ng/ml) caused a decrease (2-fold - statistically insignificant) in expression of examined oncogenes, compared to that of the control group.In summary, this data indicates that 60 ng/ml paclitaxel dose induced the RAB gene expression in an up-regulated pathway. A higher concentration of cytostatic (300 ng/ml) is a toxic dose for primary breast cells in vitro