Protein Phosphatase Inhibitor-1 has protective activities in stress conditions in E.coli

Abstract

Protein phosphatase inhibitor-1 (PPI-1) is a major inhibitor of protein phosphatase 1 (PPI), which regulates signal transduction in many eukaryotic cellular processes. Biophysical studies have shown that PPI-1 has a large Stokes radius and is heat stable, Suggesting that it lacks extensive secondary structures. The unfolded structure of PPI-1 may enable it to interact with many proteins or ligands during stress conditions. Here we show that PPI-1 can act as a protective molecule, inhibiting protein aggregation and guarding E. coli cells against various stresses. Therefore, PPI-1 seems to have a physiological function as a protective molecule as well as regulator of protein serine/threonine phosphatases. (c) 2006 Elsevier B.V. All rights reserved.