DNAH8
Developmental stage
Expression is detected in the germ cells from the early spermatocyte to late spermatid stages but not in the somatic cells (Leydig, Sertoli cells).
Domain
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.
Function
Force generating protein component of the outer dynein arms (ODAs) in the sperm flagellum. Produces force towards the minus ends of microtubules. Dynein has ATPase activity; the force-producing power stroke is thought to occur on release of ADP. Involved in sperm motility; implicated in sperm flagellar assembly.
Involvement in disease
Spermatogenic failure 46
SPGF46
An autosomal recessive infertility disorder caused by spermatogenesis defects resulting in asthenoteratozoospermia. SPGF46 is characterized by multiple morphologic abnormalities of sperm flagella with disorganization of axonemal and periaxonemal structures. Flagella are absent, short, coiled, angulated, and/or of irregular caliber.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the dynein heavy chain family.
Tissue Specificity
Expressed in spermatozoa (at protein level). Not detected in airway epithelial cells (at protein level).
Cellular localization
- Cytoplasm
- Cytoskeleton
- Flagellum axoneme
- Cytoplasm
- Detected in sperm tail, with almost exclusive localization to the principal piece. Also detected in the cytoplasm of primary spermatocytes.
Alternative names
Dynein axonemal heavy chain 8, Axonemal beta dynein heavy chain 8, Ciliary dynein heavy chain 8, DNAH8