Ferritins are ubiquitous proteins that oxidise and store iron within a protein shell to protect cells from oxidative damage. We have characterized the structure and function of a new member of the ferritin superfamily that is sequestered within an encapsulin capsid. We show that this encapsulated ferritin (EncFtn) has two main alpha helices, which assemble in a metal dependent manner to form a ferroxidase center at a dimer interface. EncFtn adopts an open decameric structure that is topologically distinct from other ferritins. While EncFtn acts as a ferroxidase, it cannot mineralize iron. Conversely, the encapsulin shell associates with iron, but is not enzymatically active, and we demonstrate that EncFtn must be housed within the encapsulin for iron storage. This encapsulin nanocompartment is widely distributed in bacteria and archaea and represents a distinct class of iron storage system, where the oxidation and mineralization of iron are distributed between two proteins.DOI: http://dx.doi.org/10.7554/eLife.18972.001

The Vesicle-associated membrane protein (VAMP)-Associated Protein B (VAPB) is the causative gene of amyotrophic lateral sclerosis 8 (ALS8) in humans. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by selective death of motor neurons leading to spasticity, muscle atrophy and paralysis. VAP proteins have been implicated in various cellular processes, including intercellular signalling, synaptic remodelling, lipid transport and membrane trafficking and yet, the molecular mechanisms underlying ALS8 pathogenesis remain poorly understood. We identified the conserved phosphoinositide phosphatase Sac1 as a Drosophila VAP (DVAP)-binding partner and showed that DVAP is required to maintain normal levels of phosphoinositides. Downregulating either Sac1 or DVAP disrupts axonal transport, synaptic growth, synaptic microtubule integrity and the localization of several postsynaptic components. Expression of the disease-causing allele (DVAP-P58S) in a fly model for ALS8 induces neurodegeneration, elicits synaptic defects similar to those of DVAP or Sac1 downregulation and increases phosphoinositide levels. Consistent with a role for Sac1-mediated increase of phosphoinositide levels in ALS8 pathogenesis, we found that Sac1 downregulation induces neurodegeneration in a dosage-dependent manner. In addition, we report that Sac1 is sequestered into the DVAP-P58S-induced aggregates and that reducing phosphoinositide levels rescues the neurodegeneration and suppresses the synaptic phenotypes associated with DVAP-P58S transgenic expression. These data underscore the importance of DVAP–Sac1 interaction in controlling phosphoinositide metabolism and provide mechanistic evidence for a crucial role of phosphoinositide levels in VAP-induced ALS.

This paper addresses the problems of designing, building and using mobile robots for urban site modeling. It presents work on both system and algorithmic aspects. On the system level, we have designed and built a functioning autonomous mobile robot. The design extends an existing robotic vehicle with a sensor suite consisting of a digital compass with an integrated inclinometer, a global positioning unit, and a camera mounted on a pan-tilt head. The system is controlled by a distributed software architecture for mobile robot navigation and site modeling. On the algorithmic level, we have developed a localization system that employs two methods. The first method uses odometry, the compass module and the global positioning sensor. An extended Kalman filter integrates the sensor data and keeps track of the uncertainty associated with it. The second method is based on camera pose estimation. It is used when the uncertainty from the first method becomes very large. The pose estimation is done by matching linear features in the image with a simple and compact environmental model. We have demonstrated the functionality of the robot and the localization methods with realworld experiments.

Synopsis An automated robotic system for protein streak seeding is described, which uses novel silicon microtools in place of the commonly used boar bristles.Abstract This report presents a new approach to streak seeding based on custom-designed silicon microtools. Experimental data shows that the microtools produce similar results to the commonly-used boar bristles. One advantage to using silicon is that it is rigid and can easily serve as an accurately calibrated end-effector on a microrobotic system. Additionally, the fabrication technology allows for the production of microtools of various shapes and sizes. A working prototype of an automatic streak seeding system based on these microtools was built and successfully applied for protein crystallization.

This paper addresses the problem of mobile robot localization in urban environments. apically, GPS is the prefemd sewor for outdoor opemtion. However, using GPS-only lodization methods leads to significant performance degradation in urban areus where toll nearby structures obstruct the clear view of the satellites. In our work, we use vision-based techniques to supplement GPS and odometry and provide accurate localization. The vision system identifies prominent linear features in the scene and matches them with a reduced model of nearby buildings, yielding improved pose estimation of the mbot. 'This work wa8 supported in part by NSF grants IIS-01-21239 and ANI-0099184.