The yeast halotolerance determinant Hal3p is an inhibitory subunit of the Ppz1p Ser/Thr protein phosphatase

• DOI: 10.1073/pnas.95.13.7357
• Publication Date: 2002-07-26T14:40:52Z
• Authors: Eulàlia de Nadal; Josep Clotet; Francesc Posas; Ramón Serrano; Néstor Gomez; Joaquín Ariño
• Keywords: 0303 health sciences; Binding Sites; Saccharomyces cerevisiae Proteins; Protein Conformation; Cell Cycle; Cell Cycle Proteins; Saccharomyces cerevisiae; Catalysis; Fungal Proteins; 03 medical and health sciences; Escherichia coli; Phosphoprotein Phosphatases; Protein Binding

Components of cellular stress responses can be identified by correlating changes in tolerance with gain or loss function defined genes. Previous work has shown that yeast cells deficient Ppz1 protein phosphatase overexpressing Hal3p, a novel regulatory unknown function, exhibit increased resistance to sodium and lithium, whereas lacking Hal3p display sensitivity. These effects are largely result expression ENA1, encoding the major cation extrusion pump cells. Disruption overexpression HAL3 (also known as SIS2) no effect on salt absence PPZ1, suggesting might upstream Ppz1p signal transduction pathway. is recovered from crude homogenates using immobilized, bacterially expressed fused glutathione S-transferase, it also copurifies affinity-purified S-transferase-Ppz1p extracts. In both cases, interaction stronger when only carboxyl-terminal catalytic domain expressed. vitro experiments reveal activity inhibited Hal3p. Overexpression suppresses reduced growth rate because aggravates lytic phenotype slt2/mpk1 mitogen-activated kinase mutant (thus mimicking deletion PPZ1). Therefore, modulate diverse physiological functions phosphatase, such cell cycle progression, acting inhibitory subunit.