5 research outputs found
Plasmodium falciparum ATG8 implicated in both autophagy and apicoplast formation
Amino acid utilization is important for the growth of the erythrocytic stages of the human malaria parasite Plasmodium falciparum, however the molecular mechanism that permits survival of the parasite during conditions of limiting amino acid supply is poorly understood. We provide data here suggesting that an autophagy pathway functions in P. falciparum despite the absence of a typical lysosome for digestion of the autophagosomes. It involves PfATG8, which has a C-terminal glycine which is absolutely required for association of the protein with autophagosomes. Amino acid starvation provoked increased colocalization between PfATG8- and PfRAB7-labeled vesicles and acidification of the colabeled structures consistent with PfRAB7-mediated maturation of PfATG8-positive autophagosomes; this is a rapid process facilitating parasite survival. Immuno-electron microscopic analyses detected PfRAB7 and PfATG8 on double-membrane-bound vesicles and also near or within the parasite's food vacuole, consistent with autophagosomes fusing with the endosomal system before being routed to the food vacuole for digestion. In nonstarved parasites, PfATG8, but not PfRAB7, was found on the intact apicoplast membrane and on apicoplast-targeted vesicles and apicoplast remnants when the formation of the organelle was disrupted; a localization also requiring the C-terminal glycine. These findings suggest that in addition to a classical role in autophagy, which involves the PfRAB7-endosomal system and food vacuole, PfATG8 is associated with apicoplast-targeted vesicles and the mature apicoplast, and as such contributes to apicoplast formation and maintenance. Thus, PfATG8 may be unique in having such a second role in addition to the formation of autophagosomes required for classical autophagy
Hierarchical phosphorylation of apical membrane antigen 1 is required for efficient red blood cell invasion by malaria parasites
Central to the pathogenesis of malaria is the proliferation of Plasmodium falciparum parasites within human erythrocytes. Parasites invade erythrocytes via a coordinated sequence of receptor-ligand interactions between the parasite and host cell. One key ligand, Apical Membrane Antigen 1 (AMA1), is a leading blood-stage vaccine and previous work indicates that phosphorylation of its cytoplasmic domain (CPD) is important to its function during invasion. Here we investigate the significance of each of the six available phospho-sites in the CPD. We confirm that the cyclic AMP/protein kinase A (PKA) signalling pathway elicits a phospho-priming step upon serine 610 (S610), which enables subsequent phosphorylation in vitro of a conserved, downstream threonine residue (T613) by glycogen synthase kinase 3 (GSK3). Both phosphorylation steps are required for AMA1 to function efficiently during invasion. This provides the first evidence that the functions of key invasion ligands of the malaria parasite are regulated by sequential phosphorylation steps
Additional file 6: Figure S5. of GMP-conformant on-site manufacturing of a CD133+ stem cell product for cardiovascular regeneration
Representative ISHAGE-based gating strategy used for the quality control of the automatically generated cell product (CP). Debris was excluded from CD45+ cells (a). CD34+ cells were selected from viable CD45+ cells (b). Events with high expression of the CD45 marker were excluded from viable CD45+/CD34+cells (c). FSC/SSC backgate was employed to select viable CD45+/CD34+ hematopoietic progenitor cells (HPCs) with blast morphology (d). Viable CD45+/CD34+/CD133+ cells were selected (e). Events with high expression of the CD45 marker were excluded from viable CD45+/CD34+/CD133+ cells (f). FSC/SSC backgate was employed to select viable CD45+/CD34+/CD133+ HPCs with blast morphology (g). A control gate (‘Ly’, lymphocytes) was used during exclusion of mature CD45+ HSCs. Red: target cell population. Gray: dead cells. (PDF 374 kb
Additional file 3: Table S2. of GMP-conformant on-site manufacturing of a CD133+ stem cell product for cardiovascular regeneration
Overview of data obtained from manual cell isolation. Volumes of bone marrow (BM) samples were ascertained by visual control. Total numbers of viable CD133+ cells were determined using Neubauer hemocytometer. The frequencies of viable CD133+ cells were measured by flow cytometry in accordance with ISHAGE guidelines. (DOC 36Â kb
A research data management (RDM) community for ELIXIR
Research data management (RDM) is central to the implementation of the FAIR (Findable Accessible, Interoperable, Reusable) and Open Science principles. Recognising the importance of RDM, ELIXIR Platforms and Nodes have invested in RDM and launched various projects and initiatives to ensure good data management practices for scientific excellence. These projects have resulted in a rich set of tools and resources highly valuable for FAIR data management. However, these resources remain scattered across projects and ELIXIR structures, making their dissemination and application challenging. Therefore, it becomes imminent to coordinate these efforts for sustainable and harmonised RDM practices with dedicated forums for RDM professionals to exchange knowledge and share resources.The proposed ELIXIR RDM Community will bring together RDM experts to develop ELIXIR’s vision and coordinate its activities, taking advantage of the available assets. It aims to coordinate RDM best practices and illustrate how to use the existing ELIXIR RDM services. The Community will be built around three integral pillars, namely, a network of RDM professionals, RDM knowledge management and RDM training expertise and resources. It will also engage with external stakeholders to leverage benefits and provide a forum to RDM professionals for regular knowledge exchange, capacity building and development of harmonised RDM practices, keeping in line with the overall scope of the RDM Community.In the short term, the Community aims to build upon the existing resources and ensure that the content of these remain up to date and fit for purpose. In the long run, the Community will aim to strengthen the skills and knowledge of its RDM professionals to support the emerging needs of the scientific community. The Community will also devise an effective strategy to engage with other ELIXIR structures and international stakeholders to influence and align with developments and solutions in the RDM field