| Abstrakt: |
Biochemical and genetic data on the metabolism of inositol phosphates in the microorganism Dictyosteliumare combined in a scheme composed of in five subroutes. The first subroute is the inositol cycle as found in other organisms: inositol is incorporated into phospholipids that are hydrolysed by PLC producing Ins(1,4,5)P3which is dephosphorylated to inositol. The second subroute is the sequential phosphorylation of inositol to InsP6; the Ins(3,4,6)P3intermediate does not release Ca2+. The third subroute is the sequential phosphorylation of Ins(1,4,5)P3to InsP6in a nucleus associated fraction, whereas the fourth subroute is the dephosphorylation of Ins(1,3,4,5,6)P5to Ins(1,4,5)P3at the plasma membrane. This last route mediates Ins(1,4,5)P3formation in cells with a disruption of the single PLCgene. Finally, we recognize the formation of InsP7and InsP8as the fifth subroute. |
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