1,4,5-trisphosphate 3-kinase A ( IP3 kinase A) is the enzyme that
terminates the IP3 signal cascade by modifying it to IP4.
IP3 is produced from phosphatidyl inositol 4,5-bis phosphate (PIP2)
by activated phospholipase C, IP3 then opens calcium
gates usually on the ER or microsomes. IP3kinaseA has been
found to bind directly to F-actin via a proline rich N-terminus domain
consisting of 66 amino-acids (Schell
et al, 2001).
IP3kinaseA co localizes with F-actin in dendritic spines of cultured
hippocampal neurons and in HeLa cells when it was artificially expressed as a
GFP fusion protein.
Schell, M. J., Erneux, C. & Irvine, R. F.
(2001) Inositol 1,4,5-trisphosphate 3-kinase A associates with F-actin and
dendritic spines via its N terminus., J.Biol.Chem. 276, 37537-37546.