The research involves analysis of the mechanism of action of the E. coli SecB protein in recognition of proteins destined to be exported out of the cell cytoplasm. Genetic studies will determine what features of the exported protein are recognized by SecB protein and what part of SecB protein is involved in the recognition. In addition, biochemical studies will determine the effects of secB mutations on protein translocation in vitro and characterize any interactions that might exist between SecB protein and polysomes that are translating exported proteins. For future research, these experiments will be extended to a detailed analysis of the interaction between SecB protein and its substrate. A second goal is to identify, through mutant isolation, other protein export factors that function like SecB protein but are specific for a different spectrum of exported proteins. Bacause secB mutations afect the export of only a subset of exported proteins, there is at lease one SecB-independent pathway for protein export. This pathway may include a factor that is functionally analogous to SecB protein. If this model is correct, the use of multiple pathways could provide the cell with a means with which to regulate the sites and rates of exort of different proteins. For orderly cell growth, the assembly of subcellular structures must be carefully controlled; the long term goal of this research is to understand the mechanism that allows the cell to perform this basic function.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM036415-01
Application #
3290341
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1986-08-01
Project End
1989-07-31
Budget Start
1986-08-01
Budget End
1987-07-31
Support Year
1
Fiscal Year
1986
Total Cost
Indirect Cost
Name
Tufts University
Department
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02111
Woodbury, R L; Topping, T B; Diamond, D L et al. (2000) Complexes between protein export chaperone SecB and SecA. Evidence for separate sites on SecA providing binding energy and regulatory interactions. J Biol Chem 275:24191-8
Cook, H A; Kumamoto, C A (1999) Overproduction of SecA suppresses the export defect caused by a mutation in the gene encoding the Escherichia coli export chaperone secB. J Bacteriol 181:3010-7
Volkert, T L; Baleja, J D; Kumamoto, C A (1999) A highly mobile C-terminal tail of the Escherichia coli protein export chaperone SecB. Biochem Biophys Res Commun 264:949-54
Muren, E M; Suciu, D; Topping, T B et al. (1999) Mutational alterations in the homotetrameric chaperone SecB that implicate the structure as dimer of dimers. J Biol Chem 274:19397-402
Fekkes, P; de Wit, J G; van der Wolk, J P et al. (1998) Preprotein transfer to the Escherichia coli translocase requires the co-operative binding of SecB and the signal sequence to SecA. Mol Microbiol 29:1179-90
Francetic, O; Kumamoto, C A (1996) Escherichia coli SecB stimulates export without maintaining export competence of ribose-binding protein signal sequence mutants. J Bacteriol 178:5954-9
Kimsey, H H; Dagarag, M D; Kumamoto, C A (1995) Diverse effects of mutation on the activity of the Escherichia coli export chaperone SecB. J Biol Chem 270:22831-5
McFarland, L; Francetic, O; Kumamoto, C A (1993) A mutation of Escherichia coli SecA protein that partially compensates for the absence of SecB. J Bacteriol 175:2255-62
Francetic, O; Hanson, M P; Kumamoto, C A (1993) prlA suppression of defective export of maltose-binding protein in secB mutants of Escherichia coli. J Bacteriol 175:4036-44
Gannon, P M; Kumamoto, C A (1993) Mutations of the molecular chaperone protein SecB which alter the interaction between SecB and maltose-binding protein. J Biol Chem 268:1590-5

Showing the most recent 10 out of 17 publications