Shinsuke Niwa

Kinesin motor proteins transport intracellular cargoes throughout cells by hydrolyzing ATP and moving along microtubule tracks. Intramolecular autoinhibitory interactions have been shown for several kinesins in vitro; however, the physiological significance of autoinhibition remains poorly understood. Here, we identified four mutations in the stalk region and motor domain of the synaptic vesicle (SV) kinesin UNC-104/KIF1A that specifically disrupt autoinhibition. These mutations augment both mic

Microtubule associated protein Collapsin response mediator protein 2 (CRMP2) regulates neuronal polarity in developing neurons through interactions with tubulins or microtubules. However, how CRMP2 promotes axonal formation by affecting microtubule behavior remains unknown. This study aimed to obtain the structural basis for CRMP2-tubulin/microtubule interaction in the course of axonogenesis. The X-ray structural studies indicated that the main interface to the soluble tubulin-dimer is the last

Defects in cilia cause a spectrum of diseases known as ciliopathies. Nephronophthisis, a ciliopathy, is the most common genetic cause of renal disease. Here, I cloned and analysed a nephronophthisis-related gene ift-139 in Caenorhabditis elegans. ift-139 was exclusively expressed in ciliated neurons in C. elegans. Genetic and cellular analyses suggest that ift-139 plays a role in retrograde intraflagellar transport and is required for cilia formation. A homologous point mutation that causes cili

Studies on Caenorhabditis elegans would benefit from the introduction of new selectable markers to allow more complex types of experiments to be conducted with this model animal. We established a new antibiotic selection marker for C. elegans transformation based on nourseothricin (NTC) and its resistance-encoding gene, streptothricin-acetyl transferase 2 (Sat2). NTC was able to efficiently prevent worm development at very low concentrations, and the worms expressing Sat2 were able to survive on

Axonal transport and intraflagellar transport (IFT) are essential for axon and cilia morphogenesis and function. Kinesin superfamily proteins and dynein are molecular motors that regulate anterograde and retrograde transport, respectively. These motors use microtubule networks as rails. Caenorhabditis elegans (C. elegans) is a powerful model organism to study axonal transport and IFT in vivo. Here, I describe a protocol to observe axonal transport and IFT in living C. elegans. Transported cargo

Dynein is a microtubule-dependent motor protein required for cell division, retrograde intracellular transport, and intraflagellar transport (IFT). Dynein 1 and dynein 2 serve as molecular motors in the cytoplasm and cilia, respectively. Each dynein consists of multiple subunits. Although the components of dynein 1 and dynein 2 are different and specific in most species, a previous study has suggested that dynein intermediate chain subunit DYCI-1 is shared by both dynein 1 and 2 in Caenorhabditi

KIF1A/UNC-104 proteins, which are members of the kinesin superfamily of motor proteins, play a pivotal role in the axonal transport of synaptic vesicles and their precursors. Drosophila melanogaster UNC-104 (DmUNC-104) is a relatively recently discovered Drosophila kinesin. Although some point mutations that disrupt synapse formation have been identified, the biochemical properties of the DmUNC-104 protein have not been investigated. Here, we prepared recombinant full-length DmUNC-104 protein an