Thermal perception is an essential physiological system for responding to ambient temperature fluctuations, and thus likely plays crucial roles in evolutionary adaptation. Thermosensitive transient receptor potential (thermoTRP) channels serve as temperature sensors. They are multimodal receptors that are activated by thermal stimuli as well as various chemicals. The properties of thermoTRP channels have varied among diverse animal species. In addition, comparative analyses among closely related species inhabiting different thermal niches revealed that property of thermoTRP channels changed during adaptation processes. Here we introduce evolutionary changes and their structural basis for the functional diversity of thermoTRP channels.
In vivo nano-imaging is today’s key technology for understanding cellular and molecular functions on a real-time basis in living organisms. In mammals, including humans, the heart sends blood to the lungs and to the rest of the body each time it beats, only under the in vivo conditions. However, to date, sarcomeric contractions, which are the basis of myocardial dynamic behavior, have not been directly observed in vivo due to technical hurdles. In this article, we describe our newly developed in vivo cardiac nano-imaging microscope for mice, and discuss recent, novel findings obtained under true physiologic conditions by using this cutting-edge technology.
Pathogenic bacteria possess specialized secretion systems on their surface. These are nanomachines that aim to transport bacterial virulence factors into host cell cytosol. The type IV secretion systems, which are evolutionarily related to bacterial conjugation systems, have divergent biological functions and are classified into two subgroups, type IVA and type IVB. By using electron microscopy, we first identified the molecular structure of the core complex of the type IVB secretion system from human pathogen Legionella pneumophila. Comparative analyses with the type IVA secretion system revealed the characteristic molecular architecture of this unique nanomachine.