The function of PCSK5 (proprotein convertase subtilisin/kexin type 5, ENSG00000099139) is as follows. Serine endoprotease that processes various proproteins by cleavage at paired basic amino acids, recognizing the RXXX[KR]R consensus motif. Likely functions in the constitutive and regulated secretory pathways. Plays an essential role in pregnancy establishment by proteolytic activation of a number of important factors such as BMP2, CALD1 and alpha-integrins. {ECO:0000269|PubMed:19764806, ECO:0000269|PubMed:20555025, ECO:0000269|PubMed:22740495}.