Lecture 2 Flashcards
What is one of the most important need in bacterial pathogenesis?
-the need to secrete proteins across one or more phospholipid membranes (inside and outside transport)
what are the roles of secreted proteins across one or more phospholipid membranes
-attachment to host cells, scavenging metabolites, direct toxic activity and disrupting host cell functions
where are these protein secretion systems used by bacteria as virulence factors
-from the cytosol of the bacteria into host cells or host environment
true or false: protein secretion systems to secrete virulence factors are not divided
false they can be divided into distinct classes, based on their structure, function and specificity
true or false; all secretion systems are conserved across all bacterial species
false some are only scpecies specific
true or false: gram positive secretion systems are more complicated
false; it’s the gram - ones that are more complicated due to the two membranes
what are the gram + secretion systems
-general sec pathway
-twin arginine translocation (TAT)
-sortase
-T4SS
-T7SS (including mycobacteria)
what are the gram - secretion pathways
-general sec pathway
-TAT
-T1SS-T6SS
-T8SS-T9SS
-outer membrane vesicles
which secretion pathways are the most commonly used systems to transport proteins across the cytoplasmic membrane
-the general secretion (sec) and the twin arginine translocation (TAT)
true or false: most proteins transported by the sec and the tat pathways remain inside the cytoplasm
wrong it is in the periplasm or the inner membrane
true or false: gram - bacteria can use more than 1 secretion pathway
true
-proteins delivered to the cytoplasmic membrane or periplasm can stay in those compartments or be transported outside of the cell via another secretion system
what is the sec pathway for
-transport unfolded proteins that have an n terminal signal sequence
the sec machinery is essential for…..
bacterial viabilitu
what does the sec machinery consist of
-peripheral membrane atpase SecA
-channel composed of SecE, SecG and SecY
translocation in the sec pathways is powered by….
-secA catalyzed atp hydrolysis as well as the proton motive force
the signal sequence in the sec pathways is cleaved by the ….
signal peptidase (SP)
e.coli uses the sec pathwatys for … of its secretome
96%
what is the TAT secretion pathway? for ?
-it is for transporting fully folded proteins
true or false: the TAT pathway is present in all the bacteria
false it is not
proteins are targeted to the TAT machinery by…….
signal peptided with a conserved twin arginine containing motif
many exported proteins containing non-covalently bound factors (heme, metals) are secreted through….
the TAT system
the TAT system is energyzed by…
the proton motive force
several oathogens including pseudomonas aeruginosa, yersinia pseudotuberculosis and e.coli require …. for full virulence in animal infection models
a functional tat pathway
examples of p aeruginosa virulence factors that require TAT first then T2SS
-phospholipase c : hemolytic
-toxA- exotoxin A