Profilin-4 (PFN4)

Profilin-4 (PFN4) is a testis-specific member of the profilin protein family, primarily expressed during spermiogenesis in humans and mice[1][3]. Unlike other profilins, PFN4 has limited sequence homology (~30%) to other family members and lacks the classical actin/poly-L-proline binding sites, signifying specialized roles beyond general actin regulation[1]. It localizes to the acrosome–acroplaxome–manchette complex, where it is essential for the proper development of the manchette (microtubule-based structure involved in sperm head shaping) and acrosome biogenesis (a process critical for sperm function)[1]. PFN4 deficiency disrupts Golgi network and vesicle trafficking, impairs acrosome formation, and leads to abnormal sperm morphology and motility, resulting in male infertility. PFN4's unique testis-specific functions distinguish it from other profilin isoforms that have broader roles in cell motility and cytoskeletal dynamics[1][3][4].

Other names

Profilin family member 4Profilin IVprofilin-4PFN4