Ins(1,4,5)P3 is an isomer of the biologically important D-myo-inositol-1,4,5-triphosphate. Unlike its isomer, Ins(1,4,5)P3 does not evoke a rise in intracellular calcium when added to cells. It is not known if Ins(1,4,5)P3 can act as a competitive inhibitor of biologically-active inositol phosphates.
Ins(1,2)P2 (sodium salt) is one of the many inositol phosphate (InsP) isomers that could act as small, soluble second messengers in the transmission of cellular signals. The most studied InsP Ins(1,4,5)P3, is a second messenger produced in cells by phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol-4,5-biphosphate. Binding of Ins(1,4,5)P3 to its receptor on the endoplasmic reticulum results in opening of the calcium channels and an increase in intracellular calcium. Ins(1,2)P2 (tested as the D L racemic mixture) is ~1,000-fold less potent than Ins(1,4,5)P3 at initiating Ca2+ release when injected into Xenopus oocytes.
D-myo-Inositol-1,3,4,5-tetraphosphate (Ins(1,3,4,5)-P4) is formed by the phosphorylation of Ins(1,4,5)P3 by inositol 1,4,5-triphosphate 3-kinase. Ins(1,3,4,5)-P4 increases intracellular calcium levels by two distinct mechanisms: opening calcium channels on both the endoplasmic reticulum to release calcium from internal stores and on the plasma membrane to allow the influx of calcium from outside the cell.
D-myo-Inositol-1,3-phosphate (Ins(1,3)P) is a member of the inositol phosphate (InsP) molecular family that play critical roles as small, soluble second messengers in the transmission of cellular signals. The most studied InsP, Ins(1,4,5)P3 is a second messenger produced in cells by phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol-4,5-biphosphate. Binding of Ins(1,4,5)P3 to its receptor on the endoplasmic reticulum results in opening of the calcium channels and an increase in intracellular calcium. Ins(1,3)P2 can be dephosphorylated to Ins(1)P by inositol polyphosphate 3-phosphatase and further dephosphorylated to inositol by inositol monophosphatase.
D-myo-Inositol-4-phosphate (Ins(4)P1) is a member of the inositol phosphate (InsP) molecular family that play critical roles as small, soluble second messengers in the transmission of cellular signals. The most studied InsP, Ins(1,4,5)P3, is a second messenger produced in cells by phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol-4,5-diphosphate. Binding of Ins(1,4,5)P3 to its receptor on the endoplasmic reticulum results in opening of the calcium channels and an increase in intracellular calcium. Ins(4)P1 can be formed by dephosphorylation of Ins(1,4)P2 by inositol polyphosphate 1-phosphatase or dephosphorylated to inositol by inositol monophosphatase.
D-myo-Inositol-1,4,5,6-tetrahosphate (sodium salt) (Ins(1,4,5,6)-P4) is one of several different inositol oligophosphate isomers implicated in signal transduction. Production of Ins(1,4,5,6)-P4 by intestinal epithelial cells increases approximately 2-14 fold, depending on the strain and incubation time, following infection with Salmonella.[1] D-myo-Inositol-1,4,5,6-tetraphosphate (sodium salt) (Ins(1,4,5,6)-P4) is one of several different inositol oligophosphate isomers implicated in signal transduction. Production of Ins(1,4,5,6)-P4 by intestinal epithelial cells increases approximately 2-14 fold, depending on the strain and incubation time, following infection with Salmonella. Ins(1,4,5,6)-P4 antagonizes epidermal growth factor (EGF) signalling through the phosphatidylinositol 3-kinase pathway. Ins(1,4,5,6)-P4 (tested as the D L racemic mixture) is ~1,000-fold less potent than Ins(1,4,5)-P3 at initiating Ca2+ release when injected into Xenopus oocytes.[2]
D-myo-Inositol-1,4,6-phosphate (Ins(1,4,6)-P3) is a member of the inositol phosphate (InsP) family that play critical roles as small, soluble second messengers in the transmission of cellular signals. The most studied InsP, Ins(1,4,5)-P3, is a second messenger produced in cells by phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositol-4,5-biphosphate. Binding of Ins(1,4,5)-P3 to its receptor on the endoplasmic reticulum results in opening of the calcium channels and an increase in intracellular calcium. Ins(1,4,6)-P3 (tested as the meso compound) is 9-fold less potent than Ins(1,4,5)-P3 at initiating Ca2+ release when injected into Xenopus oocytes.