Placental alkaline phosphatase de-phosphorylates insulin-like growth factor (IGF)-binding protein-1

Placenta. 2014 Jul;35(7):520-2. doi: 10.1016/j.placenta.2014.04.014. Epub 2014 May 9.

Abstract

Background: Insulin-like growth factors (IGF) regulate fetal growth through their effects on placenta. Their actions are influenced by IGF binding protein-1. Phosphorylated IGFBP-1 (pIGFBP-1) has high affinity for IGF-I and usually inhibits IGF-I activity but during pregnancy, it is de-phosphorylated to generate lower affinity isoforms and consequently, increased IGF bioavailability. Here we investigate the role of placenta in this process.

Results: Our data show that term human placental explants, but not their conditioned medium, can de-phosphorylate IGFBP-1 through the action of placental alkaline phosphatase (PLAP).

Discussion: PLAP-mediated de-phosphorylation of IGFBP-1 may provide a mechanism for controlling IGF-I bioavailability and action at the maternal/fetal interface.

Keywords: IGF; IGFBP-1; Maternal; PLAP; Trophoblast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase / metabolism*
  • Female
  • Fetal Development
  • GPI-Linked Proteins / metabolism
  • Humans
  • Insulin-Like Growth Factor Binding Protein 1 / chemistry
  • Insulin-Like Growth Factor Binding Protein 1 / metabolism*
  • Insulin-Like Growth Factor I / metabolism
  • Isoenzymes / metabolism*
  • Maternal-Fetal Exchange
  • Phosphorylation
  • Placenta / metabolism*
  • Pregnancy
  • Protein Isoforms / chemistry
  • Protein Isoforms / metabolism

Substances

  • GPI-Linked Proteins
  • IGFBP1 protein, human
  • Insulin-Like Growth Factor Binding Protein 1
  • Isoenzymes
  • Protein Isoforms
  • Insulin-Like Growth Factor I
  • Alkaline Phosphatase
  • alkaline phosphatase, placental