In a previous study, we showed that the inositol pyrophosphate diphosphoinositol pentakisphosphate (IP7) physiologically phosphorylates mammalian and yeast proteins. We now report that this phosphate transfer reflects pyrophosphorylation. Thus, proteins must be prephosphorylated by ATP to prime them for IP7 phosphorylation. IP7 phosphorylates synthetic phosphopeptides but not if their phosphates have been masked by methylation or pyrophosphorylation. Moreover, IP7 phosphorylated peptides are more acid-labile and more resistant to phosphatases than ATP phosphorylated peptides, indicating a different type of phosphate bond. Pyrophosphorylation may reprissent a novel mode of signaling to proteins.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Sep 25 2007|
- Inositol polyphosphate
- Protein phosphorylation
ASJC Scopus subject areas