Biochemical Analysis of Inositol Phosphate Kinases

Lipid-derived inositol phosphates (IPs) are a complex group of second messengers generated by the sequential phosphorylation of inositol 1,4,5-trisphosphate (IP3). Synthetic pathways leading from IP3 to the formation of inositol tetrakisphosphate IP4, inositol pentakisphosphate IP5, inositol hexakisphosphate IP6, and inositol pyrophosphates PP-IPs have been elucidated in eukaryotes from yeast to human. Studies have attributed a variety of cellular functions to IPs, highlighting the importance of understanding how the pathways for their synthesis are regulated. This chapter summarizes experimental techniques for the biochemical characterization of the key inositol phosphate kinases IPKs necessary for producing the diverse array of IP species.