PRSS50 (serine protease 50) is a threonine endopeptidase primarily involved in proteolysis and protein processing, localized to the cytoplasm and endoplasmic reticulum 1. In the testis, PRSS50 is the predominant PRSS family member expressed during human spermatogenesis, with tightly regulated expression through bivalent chr3 modifications 2. Functionally, PRSS50 plays a critical role in meiotic progression and male fertility by negatively regulating the MKP3/ERK signaling pathway; PRSS50 deletion in mice impairs DNA synthesis, causes abnormal spermatid nuclear compression, reduces sex hormone levels, and increases spermatogenic cell apoptosis through dysregulated ERK1/2 phosphorylation 1. Beyond reproductive function, PRSS50 shows disease relevance in metabolic and neurological conditions. Epigenome-wide studies identified hypomethylation of PRSS50 in type 2 diabetes mellitus patients, suggesting potential involvement in glucose homeostasis 3. PRSS50 methylation changes were detected in smoking-exposed brain regions, implicating it in nicotine-related neuroadaptation 4, and in retinal tissues of age-related macular degeneration patients 5. Predicted gene expression of PRSS50 in the atrial appendage interacted with amyloid deposition on episodic memory in Alzheimer's disease cohorts 6. These findings suggest PRSS50 functions in tissue-specific proteolytic processes with broader implications for reproductive, metabolic, and neurodegenerative disease pathophysiology.