Inositol phosphate signaling and gibberellic acid.

To respond to physical signals and endogenous hormones, plants use specific signal transduction pathways. We and others have previously shown that second messenger inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] is used in abscisic acid (ABA) signaling, and that some mutants with altered Ins(1,4,5)P(3) have altered responses to ABA. Specifically, mutants defective in the myo-inositol polyphosphate 5-phosphatases (5PTases) 1 and 2 genes that hydrolyze 5-phosphates from Ins(1,4,5)P(3) and other PtdInsP and InsP substrates, have elevated Ins (1,4,5)P(3), and are ABA-hypersensitive.

A phosphatidylinositol phosphate-specific myo-inositol polyphosphate 5-phosphatase required for seedling growth.

The phosphatidylinositol phosphate signaling pathway is involved in many crucial cellular functions. The myo-inositol polyphosphate 5-phosphatases (5PTases) (E.C.

Molecular characterization of an Arabidopsis gene encoding a phospholipid-specific inositol polyphosphate 5-phosphatase.

Phosphoinositides are important molecules that serve as second messengers and bind to a complex array of proteins modulating their subcellular location and activity. The enzymes that metabolize phosphoinositides can in some cases serve to terminate the signaling actions of phosphoinositides. The inositol polyphosphate 5-phosphatases (5PTases) comprise a large protein family that hydrolyzes 5-phosphates from a variety of inositol phosphate and phosphoinositide substrates.