title: Protein phosphatase inhibitor-1 (PPI-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 (PP1), 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.
authors.affiliation: Department of Biological and Molecular Engineering, College of Engineering, Ajou University, Suwon 443-749, South Korea. doohunkim@ajou.ac.kr
authors.forename: Thomas Doohun
authors.initials: TD
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D029968:Escherichia coli Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011993:Recombinant Fusion Proteins; C021042:protein phosphatase inhibitor-1