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Background: The incidence of neurological disorders is increasing due to population growth and extended life expectancy. Despite advances in the understanding of these disorders, curative strategies for treatment have not yet eventuated. In part, this is due to the complexities of the disorders and a lack of identification of their specific underlying pathologies. Dictyostelium discoideum has provided a useful, simple model to aid in unraveling the complex pathological characteristics of neurological disorders including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, neuronal ceroid lipofuscinoses and lissencephaly. In addition, D. discoideum has proven to be an innovative model for pharmaceutical research in the neurological field. Scope of review: This review describes the contributions of D. discoideum in the field of neurological research. The continued exploration of proteins implicated in neurological disorders in D. discoideum may elucidate their pathological roles and fast-track curative therapeutics.

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Phototaxis is light‐regulated movement of motile organisms (microorganisms in the case of microbial phototaxis), usually resulting in their attraction to (positive phototaxis) or avoidance of (negative phototaxis) illuminated regions. Bacteria and archaea often use a time‐biased random walk strategy – choosing directions randomly, but moving for longer time periods in the chosen direction if it happens to be correct. They use various photoreceptors, including xanthopsins, bacteriophytochromes and sensory rhodopsins to sense light, and two‐component histidine kinase‐mediated phosphotransfer systems to regulate movement. Eukaryotic microbes, by contrast, can respond to the direction of light by regulating the direction of movement. Their phototransduction pathways involve protein serine/threonine protein kinases and regulation by second messengers. Representative organisms from each of the three taxonomic domains whose photosensory signal transduction pathways have been studied. Many components of the signal transduction pathways controlling phototaxis have been identified, but much remains to be elucidated. Key Concepts Phototaxis enables microorganisms to position themselves in an environment that is optimal for survival. Organisms from all three taxonomic domains display phototaxis with differing photosensory signal transduction pathways. Photosensory signal transduction pathways in eubacteria and archaea involve the coupling of signals from photoreceptors to the same signalling pathways as are used by these organisms for chemotaxis. Phototransduction pathways in archaea and bacteria involve two‐component signalling systems that phosphorylate/dephosphorylate proteins at histidine and aspartate residues. Phototransduction pathways in eukaryotic microbes appear to involve protein phosphorylation/dephosphorylation at serine or threonine residues, and the responsible kinases and phosphatases are regulated by second messengers.