Dynein heavy chains are minus end-directed microtubule motor proteins. Axonemal dynein complexes interact with adjacent microtubules in the axoneme. Coordinated binding and release of the axonemal dyneins slide the microtubules relative to each other causing the axoneme to bend driving ciliary and flagellar motion. They are subdivided into inner and outer arm classes depending on their position within the axoneme. (Adapted from PMID:24064538).