Polypeptide GalNAc-transferase T3 and familial tumoral calcinosis. Secretion of fibroblast growth factor 23 requires O-glycosylation

J Biol Chem. 2006 Jul 7;281(27):18370-7. doi: 10.1074/jbc.M602469200. Epub 2006 Apr 25.


Mutations in the gene encoding the glycosyltransferase polypeptide GalNAc-T3, which is involved in initiation of O-glycosylation, were recently identified as a cause of the rare autosomal recessive metabolic disorder familial tumoral calcinosis (OMIM 211900). Familial tumoral calcinosis is associated with hyperphosphatemia and massive ectopic calcifications. Here, we demonstrate that the secretion of the phosphaturic factor fibroblast growth factor 23 (FGF23) requires O-glycosylation, and that GalNAc-T3 selectively directs O-glycosylation in a subtilisin-like proprotein convertase recognition sequence motif, which blocks processing of FGF23. The study suggests a novel posttranslational regulatory model of FGF23 involving competing O-glycosylation and protease processing to produce intact FGF23.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Animals
  • Binding, Competitive
  • CHO Cells
  • Calcinosis / genetics*
  • Calcinosis / metabolism
  • Cricetinae
  • Fibroblast Growth Factor-23
  • Fibroblast Growth Factors / metabolism*
  • Glycosylation
  • Humans
  • Metabolic Diseases / genetics
  • Molecular Sequence Data
  • N-Acetylgalactosaminyltransferases / genetics
  • N-Acetylgalactosaminyltransferases / metabolism*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Polypeptide N-acetylgalactosaminyltransferase
  • Proprotein Convertases / genetics
  • Proprotein Convertases / metabolism
  • Protein Processing, Post-Translational*
  • Substrate Specificity


  • FGF23 protein, human
  • Neoplasm Proteins
  • Fibroblast Growth Factors
  • Fibroblast Growth Factor-23
  • N-Acetylgalactosaminyltransferases
  • Proprotein Convertases