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Schlagwörter:
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Zusammenfassung:
Prokaryotes possess various kinds of cell surface organelles
serving versatile biological roles depending on the environmental
niche of the organism. The formation of these structures
involves fascinating machineries, as not only do the protein
components need to travel across the cytoplasmic
membrane like all secreted proteins, but they also need to do
so in a precisely coordinated manner for proper assembly.
Most commonly found on the surface of bacteria are flagella
used for swimming (47); the type III secretion injectisome
(needle structure) (21), which is used to deliver effector molecules
from pathogenic organisms into host cells; and a wide
variety of thinner organelles that fall under the broad designation
of pili (13, 33, 58, 64, 69, 78). Different classes of these
structures (type I pili, type IV pili, sex pili, etc.) which differ
significantly in their structure, assembly, and function have
been identified. Their many roles include adhesion, twitching
(or surface) motility, and delivery of DNA and toxins, as well
as functioning as electrically conductive “nanowires.” Other,
less commonly studied appendages have also been reported,
such as spinae (9).
