Signal Recognition Particle RNA Contributes to Oxidative Stress Response in Deinococcus radiodurans by Modulating Catalase Localization
Abstract
The proper functioning of many proteins requires their transport to the correct cellular compartment or their secretion. Signal recognition particle (SRP) is a major protein transport pathway responsible for the co-translational movement of integral membrane proteins as well as periplasmic proteins.Deinococcus radioduransis a ubiquitous bacterium that expresses a complex phenotype of extreme oxidative stress resistance, which depends on proteins involved in DNA repair, metabolism, gene regulation, and antioxidant defense. These proteins are located extracellularly or subcellularly, but the molecular mechanism of protein localization inD. radioduransto manage oxidative stress response remains unexplored. In this study, we characterized the SRP complex inD. radioduransR1 and showed that the knockdown (KD) of the SRP RNA (Qpr6) reduced bacterial survival under hydrogen peroxide and growth under chronic ionizing radiation. Through LC-mass spectrometry (MS/MS) analysis, we detected 162 proteins in the periplasm of wild-typeD. radiodurans, of which the transport of 65 of these proteins to the periplasm was significantly reduced in the Qpr6 KD strain. Through Western blotting, we further demonstrated the localization of the catalases inD. radiodurans, DR_1998 (KatE1) and DR_A0259 (KatE2), in both the cytoplasm and periplasm, respectively, and showed that the accumulation of KatE1 and KatE2 in the periplasm was reduced in the SRP-defective strains. Collectively, this study establishes the importance of the SRP pathway in the survival and the transport of antioxidant proteins inD. radioduransunder oxidative stress.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 18, 2020
- Source ID
- 10.3389/fmicb.2020.613571
Entities
People
- Elena K. Gaidamakova
- Jaden Fang
- Jessie Jiang
- Lydia M Contreras
- Michael J. Daly
- Rok Tkavc
- Runhua Han
Organizations
- Air Force Office of Scientific Research
- Defense Threat Reduction Agency
- University of Texas at Austin