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FliS

FliS is a bacterial flagellar chaperone protein that participates in the assembly of the bacterial flagellum by handling the flagellin subunit FliC. Found in many Gram-negative bacteria, including Escherichia coli and Salmonella, FliS is encoded within flagellar gene clusters and is co-regulated with other motility genes.

Function is to bind soluble FliC in the cytoplasm to prevent premature self-assembly into filaments and to

Mechanism involves FliS shielding the polymerization interfaces of FliC, maintaining FliC in a secretion-competent state. Through

Genetics and regulation: The fliS gene is part of the flagellar gene hierarchy, and its expression is

Structure and interactions: FliS is a soluble cytosolic protein that forms a complex with FliC. In addition

See also: Flagellum, Flagellar assembly, FliC, Type III secretion system.

stabilize
FliC
during
transit
to
the
flagellar
export
apparatus.
The
FliS–FliC
complex
is
thought
to
interact
with
the
flagellar
type
III
secretion
system
and
facilitate
delivery
of
FliC
to
the
export
gate,
where
it
is
unfolded
and
threaded
through
the
secretion
channel
for
assembly
at
the
distal
end
of
the
growing
filament.
this
chaperone
activity,
FliS
contributes
to
efficient
flagellin
export
and
orderly
filament
assembly,
supporting
proper
rotary
motility.
coordinated
with
other
components
of
the
assembly
pathway.
Loss
of
FliS
function
generally
reduces
motility
and
can
impair
filament
formation
due
to
inefficient
export
of
flagellin.
to
FliC,
FliS
may
interact
with
components
of
the
export
machinery
such
as
FlhA
to
facilitate
substrate
delivery,
though
exact
interaction
details
can
vary
among
species.