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Robert T. Sauer. Cezairliyan, Brent (Brent O.) Massachusetts Institute of Technology. Dept. of Biology. Massachusetts Institute of Technology. Department of Biology 2008-11-07T19:17:55Z 2008-11-07T19:17:55Z 2008 2008 http://hdl.handle.net/1721.1/43224 259447976 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2008. Includes bibliographical references. The ability to adapt to changing environments is essential to survival. Bacteria have developed sophisticated means by which they sense and respond to stresses imposed by changes in the environment. I have undertaken the study of elements of the TE stress response pathway in the bacterium Escherichia coli and the orthologous pathway in the bacterium Pseudomonas aeruginosa. These pathways sense stress in the periplasm and relay the signal into the cytoplasm by a series of proteolytic cleavages of a transmembrane regulatory protein. In E. coli, I have undertaken the study of the regulation of the cleavage of transmembrane regulator RseA by the first protease, DegS. I discovered that RseB, an RseA-binding protein, inhibits cleavage of RseA by DegS. The interaction between RseA and RseB is strong and specific, and the inhibition of cleavage is independent of the autoinhibition of DegS by its PDZ domain. In P. aeruginosa, I have demonstrated that AlgW, the homolog of DegS, cleaves the transmembrane regulator MucA. I have shown similar inhibitory effects of the ortholog of RseB on the ortholog of RseA. Interestingly, the PDZ domain of AlgW appears to function differently from that of DegS. In addition, I observed that a regulatory loop in the AlgW protease plays an inhibitory role in the binding of substrate. by Brent Cezairliyan. Ph.D. 118 leaves eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Biology. Regulation of the periplasmic stress responses in E. coli and P. aeruginosa Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="3d838ce7-b886-45a4-a8e0-c1be59292178"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Regulation of the periplasmic stress responses in E. coli and P. aeruginosa</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2008</PublicationDate> <Authors> <Author> <DisplayName>Cezairliyan, Brent (Brent O.)</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Biology.</Keyword> <Abstract>The ability to adapt to changing environments is essential to survival. Bacteria have developed sophisticated means by which they sense and respond to stresses imposed by changes in the environment. I have undertaken the study of elements of the TE stress response pathway in the bacterium Escherichia coli and the orthologous pathway in the bacterium Pseudomonas aeruginosa. These pathways sense stress in the periplasm and relay the signal into the cytoplasm by a series of proteolytic cleavages of a transmembrane regulatory protein. In E. coli, I have undertaken the study of the regulation of the cleavage of transmembrane regulator RseA by the first protease, DegS. I discovered that RseB, an RseA-binding protein, inhibits cleavage of RseA by DegS. The interaction between RseA and RseB is strong and specific, and the inhibition of cleavage is independent of the autoinhibition of DegS by its PDZ domain. In P. aeruginosa, I have demonstrated that AlgW, the homolog of DegS, cleaves the transmembrane regulator MucA. I have shown similar inhibitory effects of the ortholog of RseB on the ortholog of RseA. Interestingly, the PDZ domain of AlgW appears to function differently from that of DegS. In addition, I observed that a regulatory loop in the AlgW protease plays an inhibitory role in the binding of substrate.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>