The cytoskeleton of mammalian spermatozoa

The mammalian spermatozoa are endowed with a unique cytoskeleton which consists both of ubiquitous and specific proteins, some of them arising from gene haploid transcription. In the head, a dense perinuclear layer is made of basic proteins (calicin, cylicin, etc) associated with calmodulin and actin remnants. In the flagellum, the axonemal microtubules are mainly composed of glutamylated tubulin isoforms; the periaxonemal outer dense fibers and fibrous sheath are considered as related cytoskeletal structures on the basis of some common polypeptides.