Iron metabolism in the social amoeba Dictyostelium discoideum: A role for ferric chelate reductases.

Iron is the most abundant transition metal in all living organisms and is essential for several cellular activities, including respiration, oxygen transport, energy production and regulation of gene expression. Iron starvation is used by professional phagocytes, from Dictyostelium to macrophages, as a form of defense mechanism against intracellular pathogens. Previously, we showed that Dictyostelium cells express the proton-driven iron transporter Nramp1 (Natural Resistance-Associated Macrophage Protein 1) and the homolog NrampB (Nramp2) in membranes of macropinosomes and phagosomes or of the contractile vacuole network, respectively.

The Dynamics of Aerotaxis in a Simple Eukaryotic Model.

In aerobic organisms, oxygen is essential for efficient energy production, and it acts as the last acceptor of the mitochondrial electron transport chain and as regulator of gene expression. However, excessive oxygen can lead to production of deleterious reactive oxygen species. Therefore, the directed migration of single cells or cell clumps from hypoxic areas toward a region of optimal oxygen concentration, named aerotaxis, can be considered an adaptive mechanism that plays a major role in biological and pathological processes.

Characterization of Transport Activity of SLC11 Transporters in Oocytes by Fluorophore Quenching.

Membrane proteins are involved in different physiological functions and are the target of pharmaceutical and abuse drugs. oocytes provide a powerful heterologous expression system for functional studies of these proteins. Typical experiments investigate transport using electrophysiology and radiolabeled uptake.

Dictyostelium as model for studying ubiquitination and deubiquitination.

By protein quality control and degradation, the ubiquitin system drives many essential regulatory processes such as cell cycle and division, signalling, DNA replication and repair. Therefore, dysfunctions in the ubiquitin system lead to many human disease states. However, despite the immense progress made over the last couple of decades, it appears that the ubiquitin system is more complex and multi-faced than formerly expected.

The past, present and future of Dictyostelium as a model system.

The social amoeba Dictyostelium discoideum has been a preferred model organism during the last 50 years, particularly for the study of cell motility and chemotaxis, phagocytosis and macropinocytosis, intercellular adhesion, pattern formation, caspase-independent cell death and more recently autophagy and social evolution. Being a soil amoeba and professional phagocyte, thus exposed to a variety of potential pathogens, D. discoideum has also proven to be a powerful genetic and cellular model for investigating host-pathogen interactions and microbial infections.