Abstract
Flagella and cilia are bending organelles, which generate cellular movements or extracellular fluid. Flagella and cilia from various organisms share the common “9 + 2” structure in which nine microtubule doublets surround two singlet microtubules and are linked by dynein motor proteins. However the mechanism to integrate the sliding motion of dynein into well-orchestrated bending was unknown. We have been working on structural analysis of flagella/cilia by electron cryo-tomography to elucidate the mechanism of bending motion. In this article we overview recent progress of understanding flagellar/ciliary bending motion, especially by our analysis of dynein arrangement and nucleotide-induced conformational change of dynein molecules in situ.
