sperm-associated antigen 4 protein (outer dense fiber-associated protein SPAG4)

Function

• role in organization & assembly of outer dense fibers (ODFs), a specific structure of the sperm tail
• interacts with ODF
• may associate with microtubules

Structure

• homodimer
• contains 1 Unc84 domain (SUN domain)
• although transmembrane domains are predicted, they represent hydrophobic globular domains associated with microtubules

Compartment

• membrane (putative)
• axoneme
• in spermatids, localized in the transient manchette & in the axoneme of elongating spermatids & epididymal sperm

More general terms

• membrane protein

Database

• OMIM: https://mirror.omim.org/entry/603038
• UniProt: http://www.uniprot.org/uniprot/Q9NPE6.html