Flagellar assembly in Caulobacter crescentus: a basal body P-ring null mutation affects stability of the L-ring protein
| Autor: | Urs Jenal, Christian D. Mohr, Lucy Shapiro |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | Journal of Bacteriology. 178:675-682 |
| ISSN: | 1098-5530 0021-9193 |
| DOI: | 10.1128/jb.178.3.675-682.1996 |
| Popis: | The P- and L-rings are structural components of the flagellar basal body that are positioned in the periplasmic space and outer membrane, respectively. In order to explore the mechanism of P- and L-ring assembly, we examined the effect of a null mutation in the gene encoding the P-ring subunit, FlgI, on the expression, stability, and subcellular localization of the L-ring subunit, FlgH, in Caulobacter crescentus. Transcription of the L-ring gene and synthesis of the L-ring protein were both increased in the P-ring null mutant. However, steady-state L-ring protein levels were dramatically reduced compared with those of wild type. This reduction, which was not observed in flagellar hook mutants, was due to a decreased stability of the L-ring protein. The instability of the L-ring protein was apparent throughout the cell cycle of the P-ring mutant and contrasted with the fairly constant level of L-ring protein during the cell cycle of wild-type cells. Low levels of the L-ring protein were detected exclusively in the cell envelope of cells lacking the P-ring, suggesting that, in the absence of P-ring assembly, L-ring monomers are unable to form multimeric rings and are thus subject to proteolysis in the periplasm. |
| Databáze: | OpenAIRE |
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