Pi control of the PHO regulon is a form of transmembrane signal transduction. Pi control requires PhoU, PhoB, PhoR, and the binding protein-dependent PstSCAB, Pi transporter. Both the pstSCAB-phoU and phoBR operons are derepressed 100-fold during Pi limitation. The Pst transporter and PhoU have negative regulatory roles. Apparently, a signal for Pi repression flows from the Pst transporter when all PstSCAB complexes are saturated with Pi, regardless of how few (repressed condition) or many (derepressed condition) complexes are present. This signal is somehow communicated, perhaps via PhoU, to PhoR which in turn acts as the Pi sensor. PhoB and PhoR are members of the large family of two-component regulatory systems in bacteria. PhoB is a DNA-binding protein and transcriptional activator. PhoR is an autophosphorylase, a kinase for PhoB, and (presumably) a phosphatase for PhoB-Pi; it converts PhoB between its transcriptionally active (PhoB-Pi) and inactive (free PhoB) forms. The phoBR operon is unusual because it is subject both to transcriptional and translational controls; the latter appears to involve a form of antisense RNA control that is physiologically regulated. This proposal concerns the mechanism of Pi transmembrane signal transduction involving the PstSCAB transporter, PhoU, and PhoR, and control of the phoBR operon. Molecular genetic studies are designed to define what components are involved in Pi control and determining how they interact. Biochemical studies on wild-type and mutant proteins are designed to detect critical protein-protein interactions that are predicted from an analysis of suppressor mutations. Studies on the expression of the pstSCAB-phoU and phoBR operons are designed to determine how the amounts of key gene products affects Pi control and what significant regulatory signals occur within each operon. These studies on Pi control of the PHO regulon are designed to contribute not only to our understanding of how cells regulate genes for P assimilation but also how cells recognize environmental stimuli in general.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM035392-08
Application #
2177873
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1985-01-01
Project End
1995-11-30
Budget Start
1993-12-01
Budget End
1994-11-30
Support Year
8
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Purdue University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
Baker, A S; Ciocci, M J; Metcalf, W W et al. (1998) Insights into the mechanism of catalysis by the P-C bond-cleaving enzyme phosphonoacetaldehyde hydrolase derived from gene sequence analysis and mutagenesis. Biochemistry 37:9305-15
Haldimann, A; Fisher, S L; Daniels, L L et al. (1997) Transcriptional regulation of the Enterococcus faecium BM4147 vancomycin resistance gene cluster by the VanS-VanR two-component regulatory system in Escherichia coli K-12. J Bacteriol 179:5903-13
Haldimann, A; Prahalad, M K; Fisher, S L et al. (1996) Altered recognition mutants of the response regulator PhoB: a new genetic strategy for studying protein-protein interactions. Proc Natl Acad Sci U S A 93:14361-6
Wanner, B L (1996) Signal transduction in the control of phosphate-regulated genes of Escherichia coli. Kidney Int 49:964-7
Metcalf, W W; Jiang, W; Daniels, L L et al. (1996) Conditionally replicative and conjugative plasmids carrying lacZ alpha for cloning, mutagenesis, and allele replacement in bacteria. Plasmid 35:1-13
Fisher, S L; Kim, S K; Wanner, B L et al. (1996) Kinetic comparison of the specificity of the vancomycin resistance VanSfor two response regulators, VanR and PhoB. Biochemistry 35:4732-40
Jiang, W; Metcalf, W W; Lee, K S et al. (1995) Molecular cloning, mapping, and regulation of Pho regulon genes for phosphonate breakdown by the phosphonatase pathway of Salmonella typhimurium LT2. J Bacteriol 177:6411-21
Fisher, S L; Jiang, W; Wanner, B L et al. (1995) Cross-talk between the histidine protein kinase VanS and the response regulator PhoB. Characterization and identification of a VanS domain that inhibits activation of PhoB. J Biol Chem 270:23143-9
Wanner, B L (1994) Molecular genetics of carbon-phosphorus bond cleavage in bacteria. Biodegradation 5:175-84
Metcalf, W W; Wanner, B L (1993) Mutational analysis of an Escherichia coli fourteen-gene operon for phosphonate degradation, using TnphoA' elements. J Bacteriol 175:3430-42

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