Three-dimensional architecture of outer- and inner-dynein arms in flagella revealed by cryo-electron tomography and single particle analysis

Flagella are the bending organelles to drive cells and have “9+2” structure with nine microtubule doublets connected by dynein arms, which are ATP-driven force generating apparatus. Inner dynein arms are localized on microtubule doublets with 96nm periodicity and regulate flagellar bending motion, whereas outer dynein arms, the accelerators for axonemal motion, form arrays on microtubule doublets with 24nm repeat. Our goal is to elucidate the mechanism of bending motion generated by dynein arms, which make only linear motion as a monomer on microtubules, and their regulation.