YoeB toxin is activated during thermal stress

MicrobiologyOpen

Brian D. Janssen¹  Fernando Garza-Sánchez¹ 

[1] Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California

关键词: A‐site mRNA cleavage;    mRNA turnover;    ribosome pausing;    RNase II;    tmRNA;   

DOI  :  10.1002/mbo3.272

来源: Wiley

【 摘 要 】

Abstract

Type II toxin-antitoxin (TA) modules are thought to mediate stress-responses by temporarily suppressing protein synthesis while cells redirect transcription to adapt to environmental change. Here, we show that YoeB, a ribosome-dependent mRNase toxin, is activated in Escherichia coli cells grown at elevated temperatures. YoeB activation is dependent on Lon protease, suggesting that thermal stress promotes increased degradation of the YefM antitoxin. Though YefM is efficiently degraded in response to Lon overproduction, we find that Lon antigen levels do not increase during heat shock, indicating that another mechanism accounts for temperature-induced YefM proteolysis. These observations suggest that YefM/YoeB functions in adaptation to temperature stress. However, this response is distinct from previously described models of TA function. First, YoeB mRNase activity is maintained over several hours of culture at 42°C, indicating that thermal activation is not transient. Moreover, heat-activated YoeB does not induce growth arrest nor does it suppress global protein synthesis. In fact, E. coli cells proliferate more rapidly at elevated temperatures and instantaneously accelerate their growth rate in response to acute heat shock. We propose that heat-activated YoeB may serve a quality control function, facilitating the recycling of stalled translation complexes through ribosome rescue pathways.

【 授权许可】

CC BY   
© 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.