Inactive serine protease 54 (PRSS54)

Inactive serine protease 54 (PRSS54) is a testis-specific protein in humans and mice, encoded by the PRSS54 gene. Although structurally related to serine-type endopeptidases (S1 peptidase domain), it is considered catalytically inactive. PRSS54 localizes to the acrosomal granule and inner acrosomal membrane during spermatogenesis, and is implicated in acrosome biogenesis and sperm head morphogenesis, as knockout mice exhibit acrosomal and sperm structure defects leading to subfertility[1]. Expression is restricted to testis under normal conditions, but PRSS54 (as a cancer/testis antigen, CT67) may be epigenetically reactivated in cancers, and thus could serve as a biomarker for certain malignancies or in reproductive biology[4][5]. Alternative splicing produces multiple transcript variants[5]. No direct pharmacological targeting of PRSS54 with drugs is reported, but its high specificity to testis and immunogenic potential in cancer warrant further research in biomarker and immunotherapy contexts[4].

Other names

PRSS54KLKBL4CT67FLJ25339Cancer/testis antigen 67Plasma kallikrein-like protein 4Testis tissue sperm-binding protein Li 40a[5]

No known active mechanism for drug targeting; putative function as an antigenic biomarker or indirect testis/cancer-related target[4]