Linked Life Data

7715454

Source:http://linkedlifedata.com/resource/pubmed/id/7715454

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1995-5-15
pubmed:abstractText
The KdpD protein is a membrane-located sensory kinase (or signal transducer) critically involved in the regulation of the kdpABC operon that is responsible for a high-affinity transport system in Escherichia coli. In this study, a set of KdpD mutants, each resulting in a single amino acid substitution around the membrane-spanning regions of KdpD, was isolated. Amino acid substitutions in these KdpD mutants were located non-randomly, particularly within the C-terminal half of the membrane-spanning regions. This set of KdpD mutants exhibited altered transmembrane-signalling properties in response to external K+ and other stimuli. In particular, these mutants were found to be insensitive, if not completely, to the K+ signal. However, they were able to respond to other stimuli such as high-salt stress, as in the wild type. Therefore, in contrast to the wild type, the cells carrying these mutations exhibited high levels of the steady-state expression of kdp, regardless of external K+, provided that high concentrations of ionic solutes were supplemented to the cultures. More interestingly, the set of KdpD mutants could also respond to high concentrations of external non-ionic solutes such as sucrose and D-arabinose, thereby increasing substantially the steady-state expression of kdp in response to the medium osmolarity. Furthermore, it was found that certain chemicals, ethanol, chlorpromazine and procaine, could function as effectors for the KdpD mutants at relatively low concentrations in the media. Based on these findings, we have examined the primary signal(s) that regulates the function of KdpD. We propose here that KdpD can be considered to be an environmental sensor that exhibits sensing mechanisms in response to both the level of K+ and the physico-chemical state of the cytoplasmic membrane.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:geneSymbol
kdpABC, kdpD, lacZ
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
929-38
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Signal-sensing mechanisms of the putative osmosensor KdpD in Escherichia coli.
pubmed:affiliation
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't