Pappalysin-1
Developmental stage
Present in serum and placenta during pregnancy; levels increase throughout pregnancy.
Function
Metalloproteinase which specifically cleaves IGFBP-4 and IGFBP-5, resulting in release of bound IGF. Cleavage of IGFBP-4 is dramatically enhanced by the presence of IGF, whereas cleavage of IGFBP-5 is slightly inhibited by the presence of IGF.
Post-translational modifications
There appear to be no free sulfhydryl groups.
Sequence Similarities
Belongs to the peptidase M43B family.
Tissue Specificity
High levels in placenta and pregnancy serum. In placenta, expressed in X cells in septa and anchoring villi, and in syncytiotrophoblasts in the chorionic villi. Lower levels are found in a variety of other tissues including kidney, myometrium, endometrium, ovaries, breast, prostate, bone marrow, colon, fibroblasts and osteoblasts.
Cellular localization
- Secreted
Alternative names
Pappalysin-1, Insulin-like growth factor-dependent IGF-binding protein 4 protease, Pregnancy-associated plasma protein A, IGF-dependent IGFBP-4 protease, IGFBP-4ase, PAPP-A, PAPPA