Open AccessTranscription Elongation Factor GreA Has Functional Chaperone Activity
Author(s) -
Kun Li,
Tianyi Jiang,
Bo Yu,
Limin Wang,
Chao Gao,
Cuiqing Ma,
Ping Xu,
Yupo Ma
Publication year - 2012
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0047521
Subject(s) - transcription factor , elongation factor , chaperone (clinical) , escherichia coli , biology , heat shock protein , mutant , heat shock , microbiology and biotechnology , transcription (linguistics) , arabidopsis , heat shock factor , rna polymerase , biochemistry , hsp70 , rna , gene , medicine , ribosome , linguistics , philosophy , pathology
Background Bacterial GreA is an indispensable factor in the RNA polymerase elongation complex. It plays multiple roles in transcriptional elongation, and may be implicated in resistance to various stresses. Methodology/Principal Findings In this study, we show that Escherichia coli GreA inhibits aggregation of several substrate proteins under heat shock condition. GreA can also effectively promote the refolding of denatured proteins. These facts reveal that GreA has chaperone activity. Distinct from many molecular chaperones, GreA does not form stable complexes with unfolded substrates. GreA overexpression confers the host cells with enhanced resistance to heat shock and oxidative stress. Moreover, GreA expression in the greA/greB double mutant could suppress the temperature-sensitive phenotype, and dramatically alleviate the in vivo protein aggregation. The results suggest that bacterial GreA may act as chaperone in vivo . Conclusions/Significance These results suggest that GreA, in addition to its function as a transcription factor, is involved in protection of cellular proteins against aggregation.