Signaling properties of the escherichia coli transducer Tap /
Tap, a low-abundance transducer involved in bacterial ofilm Inc. chemotaxis, senses dipeptides via the dipeptide-binding protein (DBP). When present as the sole transducer in the cell, Tap does not generate the tumble signals that allow the bacterium to change direction, and therefore does not effec...
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733059501&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Tap, a low-abundance transducer involved in bacterial ofilm Inc. chemotaxis, senses dipeptides via the dipeptide-binding protein (DBP). When present as the sole transducer in the cell, Tap does not generate the tumble signals that allow the bacterium to change direction, and therefore does not effectively mediate chemotaxis. We studied the in vivo signaling properties of Tap by constructing functional transducer hybrids between Tap and the high-abundance transducer Tar. We show that the signaling deficiency in Tap is mainly associated with its cytoplasmic domain. The modulation of the CheA kinase activity by transducers is the critical step in regulating the chemotactic signal transduction pathway. We find that Tap neither stimulates (the tumble signal) nor inhibits (the attractant signal) the kinase activity of CheA in vitro. Therefore, we conclude that Tap must propagate its chemotactic signal via its more abundant and potent relatives, Tar and Tsr. To test this hypothesis, we used heterozygous transducers contained in the same cell membranes to determine whether an attractant signal could be communicated cooperatively among them. We present the first biochemical evidence for inter-transducer crosstalk and show that the adaptation state of the transducers has a critical effect on communication between transducers. |
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| Item Description: | Vita. "Major Subject: Biology". |
| Physical Description: | ix, 110 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references (leaves 97-108). |