Actin-like protein 9 (ACTL9)

Actin-like protein 9 (ACTL9) is a testis-specific actin-related protein predominantly expressed in the equatorial region of the sperm acrosome[3][4]. It plays a critical role in acrosome assembly and the formation of the perinuclear theca (PT), both of which are essential for proper sperm head structure and successful fertilization[3][4][2]. Pathogenic variants in ACTL9 disrupt its interaction with its paralog ACTL7A, result in the abnormal localization of the sperm-borne oocyte activation factor PLCζ, and cause failures in oocyte activation, leading to disorders such as total fertilization failure and non-syndromic male infertility due to sperm motility disorders[2][4]. There are no approved drugs directly known to target ACTL9, nor are there clinical indications of its use as a therapeutic target[3][2]. Pathogenic mutations in ACTL9 have diagnostic value as biomarkers for certain infertilities, especially those characterized by failed fertilization after assisted reproduction techniques such as intracytoplasmic sperm injection (ICSI)[2][4].

Other names

ACTL9ACTL7CHSD21MGC33407SPGF53testicular tissue protein Li 15testicular tissue protein Li 9