The type II secretion pathway is widely distributed among Gram-negative pathogens where it is responsible for extracellular secretion of toxins and degradative enzymes. At least 12 gene products located in both the cytoplasmic and outer membrane collectively comprise the type II secretion apparatus, which is specifically required for the translocation of secreted proteins from the periplasm to the extracellular milieu. This pathway is highly specific. It distinguishes secreted proteins from resident periplasmic proteins and discriminates between its own secreted proteins and those introduced from closely related species. In addition, secretion through this pathway differs from most other membrane transport systems in that its substrates consist of folded proteins. The objective of this proposal is to characterize the mechanism of type II secretion at the molecular level. The studies will utilize Vibrio cholerae and will specifically examine the secretion of cholera toxin (CT), as well as other proteins that utilize the type II pathway. CT provides an excellent model protein for these studies since its structure and function as well as its folding and assembly pathway are very well characterized. Specifically, we will test the hypotheses that: 1) Molecules secreted by the type II system encode information critical to their secretion within their tertiary structure, 2) the type II complex spans both membranes and components involved in connecting the outer membrane secretion pore with the cytoplasmic membrane regulate secretion by transducing energy to the secretion pore or by regulating its opening, 3) the secretion apparatus is localized to the poles or septum where the peptidoglycan undergoes rearrangements and/or where the pore size is atypical to allow for secretion of folded proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
7R01AI049294-04
Application #
6942505
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Hall, Robert H
Project Start
2002-03-01
Project End
2007-02-28
Budget Start
2004-07-01
Budget End
2005-02-28
Support Year
4
Fiscal Year
2004
Total Cost
$231,299
Indirect Cost
Name
University of Maryland Baltimore
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Waack, Ursula; Warnock, Mark; Yee, Andrew et al. (2018) CpaA Is a Glycan-Specific Adamalysin-like Protease Secreted by Acinetobacter baumannii That Inactivates Coagulation Factor XII. MBio 9:
Waack, Ursula; Johnson, Tanya L; Chedid, Khalil et al. (2017) Targeting the Type II Secretion System: Development, Optimization, and Validation of a High-Throughput Screen for the Identification of Small Molecule Inhibitors. Front Cell Infect Microbiol 7:380
Rule, Chelsea S; Patrick, Marcella; Sandkvist, Maria (2016) Measuring In Vitro ATPase Activity for Enzymatic Characterization. J Vis Exp :
Rule, Chelsea S; Patrick, Marcella; Camberg, Jodi L et al. (2016) Zinc coordination is essential for the function and activity of the type II secretion ATPase EpsE. Microbiologyopen 5:870-882
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Lu, Connie; Turley, Stewart; Marionni, Samuel T et al. (2013) Hexamers of the type II secretion ATPase GspE from Vibrio cholerae with increased ATPase activity. Structure 21:1707-17
Korotkov, Konstantin V; Sandkvist, Maria; Hol, Wim G J (2012) The type II secretion system: biogenesis, molecular architecture and mechanism. Nat Rev Microbiol 10:336-51

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