PAPLN (papilin, proteoglycan like sulfated glycoprotein) is a protein-coding gene located on human chromosome 14q24.2 that encodes a secreted glycoprotein belonging to the papilin family . Predicted to function as a serine-type endopeptidase inhibitor, PAPLN contains multiple conserved domains including thrombospondin type 1 repeats, Kunitz/BPTI domains, and immunoglobulin-like domains, which are characteristic of protease inhibitors involved in extracellular matrix organization . The protein is primarily localized to the basement membrane and plays a role in extracellular matrix organization and nervous system development . PAPLN is broadly expressed across human tissues, with highest expression levels observed in the spleen and kidney . Emerging research suggests its involvement in pelvic organ prolapse etiopathogenesis, highlighting its potential significance in connective tissue integrity .