Sensing of volume changes by poterioochromonas involves a ca-regulated system which controls activation of isofloridoside-phosphate synthase.

Article Details

Citation

Copy to clipboard

Kauss H

Sensing of volume changes by poterioochromonas involves a ca-regulated system which controls activation of isofloridoside-phosphate synthase.

Plant Physiol. 1981 Aug;68(2):420-4.

PubMed ID

16661928 [ View in PubMed

]

Abstract

In Poterioochromonas, osmotically induced shrinkage is reversed by an accumulation of isofloridoside. In crude extracts, the isofloridosidephosphate synthase is activated by an enzyme system, the activity of which is increased at reduced cell volume and decreases again when cells reswell. The synthase-activating enzyme system also spontaneously gains activity in cell homogenates. This process is affected by the presence of ethylene glycol-bis-(2-aminoethyl ether)-N,N-tetraacetate or ethylenediaminetetraacetate in the homogenization buffer and can also be irreversibly initiated by addition of Ca(2+) ions to homogenates. Pretreatment of the cells with the Ca(2+)-ionophore A 23187 also enhances spontaneous operation of the activation system in homogenates. Addition of the calmodulin-binding drugs trifluoperazine, fluphenazine, or chlorpromazine to homogenates promotes the activation process. The results suggest that detection of volume changes involves a Ca(2+)-controlled and possibly calmodulin-mediated reaction sequence located in membranes. This mechanism might involve zymogens and, after stimulation by cell shrinkage, appears to produce or activate a specific protease capable of activating the isofloridosidephosphate synthase.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Fluphenazine	Calmodulin	Protein	Humans	Unknown	Inhibitor	Details