Tomohiro Nishizawa

Learn More
Channelrhodopsins (ChRs) are light-gated cation channels derived from algae that have shown experimental utility in optogenetics; for example, neurons expressing ChRs can be optically controlled with high temporal precision within systems as complex as freely moving mammals. Although ChRs have been broadly applied to neuroscience research, little is known(More)
Ca(2+)/cation antiporters catalyze the exchange of Ca(2+) with various cations across biological membranes to regulate cytosolic calcium levels. The recently reported structure of a prokaryotic Na(+)/Ca(2+) exchanger (NCX_Mj) revealed its overall architecture in an outward-facing state. Here, we report the crystal structure of a H(+)/Ca(2+) exchanger from(More)
Tight junctions are cell-cell adhesion structures in epithelial cell sheets that surround organ compartments in multicellular organisms and regulate the permeation of ions through the intercellular space. Claudins are the major constituents of tight junctions and form strands that mediate cell adhesion and function as paracellular barriers. We report the(More)
PIWI-interacting RNAs (piRNAs) silence transposons to maintain genome integrity in animal germ lines. piRNAs are classified as primary and secondary piRNAs, depending on their biogenesis machinery. Primary piRNAs are processed from long non-coding RNA precursors transcribed from piRNA clusters in the genome through the primary processing pathway. Although(More)
Krokinobacter eikastus rhodopsin 2 (KR2) is the first light-driven Na(+) pump discovered, and is viewed as a potential next-generation optogenetics tool. Since the positively charged Schiff base proton, located within the ion-conducting pathway of all light-driven ion pumps, was thought to prohibit the transport of a non-proton cation, the discovery of KR2(More)
Magnesium is the most abundant divalent cation in living cells and is crucial to several biological processes. MgtE is a Mg(2+) channel distributed in all domains of life that contributes to the maintenance of cellular Mg(2+) homeostasis. Here we report the high-resolution crystal structures of the transmembrane domain of MgtE, bound to Mg(2+), Mn(2+) and(More)
The drug/metabolite transporter (DMT) superfamily is a large group of membrane transporters ubiquitously found in eukaryotes, bacteria and archaea, and includes exporters for a remarkably wide range of substrates, such as toxic compounds and metabolites. YddG is a bacterial DMT protein that expels aromatic amino acids and exogenous toxic compounds, thereby(More)
SWEET family proteins mediate sugar transport across biological membranes and play crucial roles in plants and animals. The SWEETs and their bacterial homologues, the SemiSWEETs, are related to the PQ-loop family, which is characterized by highly conserved proline and glutamine residues (PQ-loop motif). Although the structures of the bacterial SemiSWEETs(More)
YidC, a member of the YidC/Oxa1/Alb3 family, inserts proteins into the membrane and facilitates membrane-protein folding in bacteria. YidC plays key roles in both Sec-mediated integration and Sec-independent insertion of membrane proteins. Here, Bacillus halodurans YidC2, which has five transmembrane helices conserved among the other family members, was(More)
  • 1