As part of the axonemal inner dynein arm complex plays a central role in ciliary beat (PubMed:30811583). Expressed in sperm flagellum, it is required for sperm motility (PubMed:30811583). Dyneins are microtubule-based molecular motors possessing ATPase activities that can convert the chemical energy of ATP into relative sliding between adjacent microtubule doublets to generate ciliary bending (PubMed:30811583). Part of the axonemal inner dynein arm complex that consists of at least two heavy chains and a number of intermediate and light chains (PubMed:30811583). Interacts with DNAI4 (By similarity). Expressed primarily in trachea and testis, 2 tissues containing axonemal structures. Also expressed in lung. Expressed in spermatozoa (at protein level) (PubMed:31178125). Dynein heavy chains probably consist of an N-terminal stem (which binds cargo and interacts with other dynein components), and the head or motor domain. The motor contains six tandemly-linked AAA domains in the head, which form a ring. A stalk-like structure (formed by two of the coiled coil domains) protrudes between AAA 4 and AAA 5 and terminates in a microtubule-binding site. A seventh domain may also contribute to this ring; it is not clear whether the N-terminus or the C-terminus forms this extra domain. There are four well-conserved and two non-conserved ATPase sites, one per AAA domain. Probably only one of these (within AAA 1) actually hydrolyzes ATP, the others may serve a regulatory function (By similarity). Exon 13 is extensively edited in brain. The disease is caused by variants affecting the gene represented in this entry. Belongs to the dynein heavy chain family. Extended N-terminus.