PAPLN encodes a proteoglycan-like sulfated glycoprotein known as papilin; the implications of which are unclear in humans, or even in animal models of depression. PAPLN, also known as PPN, is located on human chromosome 14q24.2. The deduced 2,147-amino acid Drosophila protein contains a predicted N-terminal signal peptide, followed by a papilin cassette, a ser/thr-rich domain, a cys-rich repeat domain, 3 Kunitz domains, a region containing an RGD motif and 2 Ig-C2 loop domains, and a conserved C-terminal cys-rich sequence. PAPLN is associated with some diseases, including Weill-Marchesani Syndromeand Isolated Ectopia Lentis. An important paralog of this gene is ADAMTS9.