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Article Dans Une Revue Journal of Bacteriology Année : 2001

The C Terminus of sigma32 Is Not Essential for Degradation by FtsH

Résumé

ABSTRACT A key step in the regulation of heat shock genes in Escherichia coli is the stress-dependent degradation of the heat shock promoter-specific ς 32 subunit of RNA polymerase by the AAA protease, FtsH. Previous studies implicated the C termini of protein substrates, including ς 32 , as degradation signals for AAA proteases. We investigated the role of the C terminus of ς 32 in FtsH-dependent degradation by analysis of C-terminally truncated ς 32 mutant proteins. Deletion of the 5, 11, 15, and 21 C-terminal residues of ς 32 did not affect degradation in vivo or in vitro. Furthermore, a peptide comprising the C-terminal 21 residues of ς 32 was not degraded by FtsH in vitro and thus did not serve as a recognition sequence for the protease, while an unrelated peptide of similar length was efficiently degraded. The truncated ς 32 mutant proteins remained capable of associating with DnaK and DnaJ in vitro but showed intermediate (5-amino-acid deletion) and strong (11-, 15-, and 21-amino-acid deletions) defects in association with RNA polymerase in vitro and biological activity in vivo. These results indicate an important role for the C terminus of ς 32 in RNA polymerase binding but no essential role for FtsH-dependent degradation and association of chaperones.

Dates et versions

hal-04267924 , version 1 (02-11-2023)

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Toshifumi Tomoyasu, Florence Arsène, Teru Ogura, Bernd Bukau. The C Terminus of sigma32 Is Not Essential for Degradation by FtsH. Journal of Bacteriology, 2001, 183 (20), pp.5911-5917. ⟨10.1128/JB.183.20.5911-5917.2001⟩. ⟨hal-04267924⟩
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