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YaeL proteolysis of RseA is controlled by the PDZ domain of YaeL and a Gln‐rich region of RseA
Author(s) -
Kanehara Kazue,
Ito Koreaki,
Akiyama Yoshinori
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg602
Subject(s) - periplasmic space , proteolysis , biology , pdz domain , cleavage (geology) , biochemistry , cleavage factor , glutamine synthetase , microbiology and biotechnology , glutamine , enzyme , escherichia coli , amino acid , gene , rna , paleontology , fracture (geology)
σ E is an alternative sigma factor involved in a pathway of extracytoplasmic stress responses in Escherichia coli . Under normal growth conditions, σ E activity is down‐regulated by the membrane‐bound anti‐σ E protein, RseA. Extracytoplasmic stress signals induce degradation of RseA by two successive proteolytic events: DegS‐catalyzed first cleavage at a periplasmic site followed by YaeL‐mediated second proteolysis at an intramembrane region. Normally, the second reaction (site‐2 proteolysis) only occurs after the first cleavage (site‐1 cleavage). Here, we show that YaeL variants with the periplasmic PDZ domain deleted or mutated allows unregulated cleavage of RseA and consequent σ E activation. It was also found that a glutamine‐rich region in the periplasmic domain of RseA was required for the avoidance of the YaeL‐mediated proteolysis in the absence of site‐1 cleavage. These results indicate that multiple negative elements both in the enzyme (PDZ domain) and in the substrate (glutamine‐rich region) determine the strict dependence of the site‐2 proteolysis on the site‐1 cleavage.