SdeK, a histidine kinase required for Myxococcus xanthus development

Citation
Js. Pollack et M. Singer, SdeK, a histidine kinase required for Myxococcus xanthus development, J BACT, 183(12), 2001, pp. 3589-3596
Citations number
35
Categorie Soggetti
Microbiology
Journal title
JOURNAL OF BACTERIOLOGY
ISSN journal
00219193 → ACNP
Volume
183
Issue
12
Year of publication
2001
Pages
3589 - 3596
Database
ISI
SICI code
0021-9193(200106)183:12<3589:SAHKRF>2.0.ZU;2-M
Abstract
The sdeK gene is essential to the Myxococcus xanthus developmental process, We reported previously, based on sequence analysis (A. G, Garza, J, S, Pol lack, B, Z, Harris, A. Lee, I, M, Keseler, E, F, Licking, and M, Singer, J, Bacteriol. 180:4628-4637, 1998), that SdeK appears to be a histidine kinas e, In the present study, we have conducted both biochemical and genetic ana lyses to test the hypothesis that SdeK is a histidine kinase, An SdeK fusio n protein containing an N-terminal polyhistidine tag (His-SdeK) displays th e biochemical characteristics of a histidine kinase, Furthermore, histidine 286 of SdeK, the putative site of phosphorylation, is required for both in vitro and in vivo protein activity, The results of these assays have led u s to conclude that SdeK is indeed a histidine kinase, The developmental phe notype of a Delta sdeK1 strain could not be rescued by codevelopment with w ild-type cells, indicating that the defect is not due to the mutant's inabi lity to produce an extracellular signal. Furthermore, the Delta sdeK1 mutan t was found to produce both A- and C-signal, based on A-factor and codevelo pment assays with a csgA mutant, respectively. The expression patterns of s everal Tn5lacZ transcriptional fusions were examined in the Delta sdeK1-nul l background, and we found that all C-signal-dependent fusions assayed also required SdeK for full expression. Our results indicate that SdeK is a his tidine kinase that is part of a signal transduction pathway which, in conce rt with the C-signal transduction pathway, controls the activation of devel opmental-gene expression required to progress past the aggregation stage.