Presentation Title

Interaction of SpcU with Pseudomonas aeruginosa’s Type III Secretion System Loading Platform

Advisor Information

Donald Rowen

Location

Dr. C.C. and Mabel L. Criss Library

Presentation Type

Poster

Start Date

7-3-2014 1:00 PM

End Date

7-3-2014 4:00 PM

Abstract

Many Gram-negative bacteria, such as Pseudomonas aeruginosa, use Type III Secretion Systems in their infection of host organisms. A Type III Secretion System is a complex system that uses a needle-like protein complex apparatus to inject toxins into target cells. Secretion of toxins through Type III Secretion Systems requires additional resources as well, including chaperone proteins which bind to the toxins before secretion. Recent studies in other organisms that utilize Type III Secretion Systems have lead to the hypothesis that these chaperone proteins may bring toxins to a three protein loading platform associated with the Type III Secretion System apparatus before they are secreted. To test this hypothesis, we are tagging homologs in P. aeruginosa of OrgA, OrgB, and SpaO; the three proteins proposed to form the loading platforms, with epitopes so that we can detect their presence in subcellular fractions. I have constructed plasmids that each express one of the three proteins tagged with a hemagglutinin (HA) epitope. Preliminary experiments indicate that two of the three are expressed and detectable in P. aeruginosa. I am currently isolating membrane fractions to determine if the proteins are located in the membrane along with the secretion apparatus. Detection of the tagged proteins in the membrane would lend support to the hypothesis that they form a loading platform associated with the secretion apparatus. Our findings will build upon our knowledge of Type III Secretion Systems which could lead to the development of drug therapies that target toxin secretion via Type III Secretion Systems.

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Mar 7th, 1:00 PM Mar 7th, 4:00 PM

Interaction of SpcU with Pseudomonas aeruginosa’s Type III Secretion System Loading Platform

Dr. C.C. and Mabel L. Criss Library

Many Gram-negative bacteria, such as Pseudomonas aeruginosa, use Type III Secretion Systems in their infection of host organisms. A Type III Secretion System is a complex system that uses a needle-like protein complex apparatus to inject toxins into target cells. Secretion of toxins through Type III Secretion Systems requires additional resources as well, including chaperone proteins which bind to the toxins before secretion. Recent studies in other organisms that utilize Type III Secretion Systems have lead to the hypothesis that these chaperone proteins may bring toxins to a three protein loading platform associated with the Type III Secretion System apparatus before they are secreted. To test this hypothesis, we are tagging homologs in P. aeruginosa of OrgA, OrgB, and SpaO; the three proteins proposed to form the loading platforms, with epitopes so that we can detect their presence in subcellular fractions. I have constructed plasmids that each express one of the three proteins tagged with a hemagglutinin (HA) epitope. Preliminary experiments indicate that two of the three are expressed and detectable in P. aeruginosa. I am currently isolating membrane fractions to determine if the proteins are located in the membrane along with the secretion apparatus. Detection of the tagged proteins in the membrane would lend support to the hypothesis that they form a loading platform associated with the secretion apparatus. Our findings will build upon our knowledge of Type III Secretion Systems which could lead to the development of drug therapies that target toxin secretion via Type III Secretion Systems.