recombinant isoenzyme A has an N-terminal 66-amino acid F-actin-binding region that localizes the kinase to dentritic spines, endogenous isoenzyme A is localized to the dentritic spines of pyramidal neurons in primary hippocampal cultures
isoform inositol 1,4,5-trisphosphate 3-kinase A is a microtubule-associated protein, and the N terminus of inositol 1,4,5-trisphosphate 3-kinase A is a critical region for direct binding to tubulin in dendritic shaft of hippocampal neurons. Protein kinase A phosphorylates residue Ser119 within inositol 1,4,5-trisphosphate 3-kinase A, leading to a significant reduction of microtubule binding affinity
isoform C is totally cytoplasmic, the N-terminal deletion mutant of InsP3 3-kinase A starting at Leu-133 and the N-terminal deletion mutant of InsP3 3-kinase B starting at Asp-483 are cytoplasmic
enrichment of IP3K-C in the nucleus after leptomycin B treatment. A nuclear export signal has evolved in the catalytic domain as a substitute for an earlier evolved corresponding N-terminal signal (IP3K-B and IP3K-C)
sequence of isoform inositol-trisphosphate 3-kinase B contains an exportin 1-dependent nuclear export signal, 134LQRELQNVQV, and the amino acids responsible for nuclear localization 129RKLR. These two targeting domains regulate the amount of nuclear IP3KB in cells. The localization of isoform inositol-trisphosphate 3-kinase B at the plasma membrane is due to its binding to cortical actin structures. All three of these targeting activities reside in one small polypeptide segment, amino acids 104-165, which acts as a multitargeting domain. In rapidly growing H1299 cells, inositol-trisphosphate 3-kinase B is specifically enriched at nuclear invaginations extending perpendicularly between the apical and basal surface of the nucleus of these flat cells
isoform C is actively transported into and out of the nucleus, a leucine-rich nuclear export signal and a nuclear import activity are localized in the N-terminal domain
IP3K-C shuttles actively between the nucleus and cytoplasm. The nuclear import and export activities of rat IP3K-C are both located in its N-terminal domain
not activated isoenzyme B: 65% soluble, 35% particulate fraction, carbachol-activated isoenzyme B shows a redistribution of enzyme from soluble to particulate fraction, only 10% remain soluble
not activated isoenzyme B: 65% soluble, 35% particulate fraction, carbachol-activated isoenzyme B shows a redistribution of enzyme from soluble to particulate fraction, only 10% remain soluble
unstimulated isoenzyme B: 65% soluble, 35% particulate fraction, carbachol-activated isoenzyme B shows a redistribution of enzyme from soluble to particulate fraction, only 10% remain soluble
unstimulated isoenzyme B: 65% soluble, 35% particulate fraction, carbachol-activated isoenzyme B shows a redistribution of enzyme from soluble to particulate fraction, only 10% remain soluble