Phosphoinositide turnover is a well established mechanism of intracellular signal transduction. Sequential phosphorylation of phosphatidylinositol (PtdIns) results inPtdIns-4-phosphate (PIP) and PtdIns-4,5-bisphosphate (PIP2). Phospholipase C (PLC)hydrolyzes PIP2 to inositol-1,4,5-trisphosphate (IP3) which stimulates release of intracellular Ca2+. PIP is generated by phosphorylation of PtdIns at the D4 position of the inositol ring. This event is mediated by the PtdIns 4-kinases (PI4-K). These enzymes are divided into two types (II and III) based on their size and sensitivity to certain compounds. Although the PI4-Ks are abundantly distributed throughout the cell, activity is found primarily in association with membranous structures. Members of this family contain a lipid kinase unique domain and a C-terminal catalytic domain. Two mammalian PI4-Ks, PI4-Kα and PI4-Kß, have been identified. PI4-Kß is homologous to the yeast PI4-K, PIK1. Based on its size and sensitivity to wortmanin (a PI3-K inhibitor), PI4-Kß is classified as a type III enzyme. Although it is found in the cytosol and in association with the Golgi, the specific function of PI4-Kß is yet to be determined.
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注意事项:
1.Since applications vary, each investigator should titrate the reagent to obtain optimal results.
2.Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.