bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 5, 2024
Abstract
Sac1
is
a
conserved
phosphoinositide
phosphatase,
whose
loss-of-function
compromises
cell
and
organism
viability.
Here,
we
employed
acute
auxin-inducible
degradation
to
identify
its
immediate
downstream
effectors
in
human
cells.
Most
of
was
degraded
∼1
h,
paralleled
by
increased
PI(4)P
decreased
cholesterol
the
trans-Golgi
network
(TGN)
during
following
hour,
superseded
Golgi
fragmentation,
impaired
glycosylation,
selective
TGN
proteins
∼4
h.
The
disintegration
resulted
from
deacidification
caused
disassembly
V-ATPase.
Mechanistically,
mediated
membrane
composition
maintained
an
assembly
promoting
conformation
V
0
a2
subunit.
Key
phenotypes
were
recapitulated
differentiated
trophoblasts,
causing
processing
defects
chorionic
gonadotropin,
line
with
intolerance
SACML1
gene.
Collectively,
our
findings
reveal
that
V-ATPase
controlled
via
fuelled
lipid
exchange.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2023,
Номер
unknown
Опубликована: Июль 31, 2023
Membranes
are
molecular
interfaces
that
compartmentalize
cells
to
control
the
flow
of
nutrients
and
information.
These
functions
facilitated
by
diverse
collections
lipids,
nearly
all
which
distributed
asymmetrically
between
two
bilayer
leaflets.
Most
models
biomembrane
structure
function
often
include
implicit
assumption
these
leaflets
have
similar
abundances
phospholipids.
Here,
we
show
this
is
generally
invalid
investigate
consequences
lipid
abundance
imbalances
in
mammalian
plasma
membranes
(PM).
Using
quantitative
lipidomics,
discovered
cytoplasmic
human
erythrocyte
>50%
overabundance
phospholipids
compared
exoplasmic
This
imbalance
enabled
an
asymmetric
interleaflet
distribution
cholesterol,
regulates
cellular
cholesterol
homeostasis.
features
produce
unique
functional
characteristics,
including
low
PM
permeability
resting
tension
leaflet
protein
localization.
largely
overlooked
aspects
membrane
asymmetry
represent
evolution
classic
paradigms
physiology.
Proceedings of the National Academy of Sciences,
Год журнала:
2024,
Номер
121(29)
Опубликована: Июль 10, 2024
In
this
study,
we
used
cryoelectron
microscopy
to
determine
the
structures
of
Flotillin
protein
complex,
part
Stomatin,
Prohibitin,
Flotillin,
and
HflK/C
(SPFH)
superfamily,
from
cell-derived
vesicles
without
detergents.
It
forms
a
right-handed
helical
barrel
consisting
22
pairs
Flotillin1
Flotillin2
subunits,
with
diameter
32
nm
at
its
wider
end
19
narrower
end.
Oligomerization
is
stabilized
by
C
terminus,
which
two
layers
linked
β-strand,
coiled-coil
domains
that
enable
strong
charge–charge
intersubunit
interactions.
interacts
membranes
both
ends;
through
SPFH1
wide
terminus
narrow
end,
facilitated
hydrophobic
interactions
lipidation.
The
inward
tilting
SPFH
domain,
likely
triggered
phosphorylation,
suggests
role
in
membrane
curvature
induction,
could
be
connected
proposed
clathrin-independent
endocytosis.
structure
shared
architecture
across
family
proteins
will
promote
further
research
into
Flotillin’s
roles
cell
biology.
Proceedings of the National Academy of Sciences,
Год журнала:
2024,
Номер
121(49)
Опубликована: Ноя. 27, 2024
Synaptic
vesicles
(SVs)
store
and
transport
neurotransmitters
to
the
presynaptic
active
zone
for
release
by
exocytosis.
After
release,
SV
proteins
excess
membrane
are
recycled
via
endocytosis,
new
SVs
can
be
formed
in
a
clathrin-dependent
manner.
This
process
maintains
complex
molecular
composition
of
through
multiple
recycling
rounds.
Previous
studies
explored
proteomic
analysis
fluorescent
microscopy,
proposing
model
an
average
(
1
).
However,
structural
heterogeneity
architecture
individual
not
well
described.
Here,
we
used
cryoelectron
tomography
visualize
details
isolated
from
mouse
brains
inside
cultured
neurons.
We
describe
several
classes
small
on
surface
long
proteinaceous
densities
SVs.
identified
V-ATPases,
determined
structure
using
subtomogram
averaging,
showed
them
forming
with
membrane-embedded
protein
synaptophysin
(Syp).
Our
bioluminescence
assay
revealed
pairwise
interactions
between
vesicle-associated
2
Syp
V-ATPase
Voe1
domains.
Interestingly,
V-ATPases
were
randomly
distributed
irrespective
vesicle
size.
A
subpopulation
neurons
contained
partially
assembled
clathrin
coat
icosahedral
symmetry.
observed
under
cages
clathrin-coated
(CCVs).
Additionally,
preparations
within
hippocampal
baskets
without
vesicles.
their
CCVs
preferential
location
proximity
cell
membrane.
advances
understanding
SVs'
diversity
architecture.
Biochemical and Biophysical Research Communications,
Год журнала:
2025,
Номер
749, С. 151384 - 151384
Опубликована: Янв. 23, 2025
Ubiquitin-like
autophagy-related
gene
ATG8
proteins
are
typically
associated
with
degradative
quality
control
via
canonical
double-membrane
macro-autophagosomes
in
the
cell.
have
now
stepped
forward
non-canonical
pathways
single
membrane
organelles.
The
growing
interest
roles
has
been
stimulated
by
recent
links
to
human
conditions,
especially
regulation
of
inflammation,
neurodegeneration
and
cancers.
Here,
we
summarize
evidence
linking
ATG8s
pathologies
acidic
V-ATPase-regulated
organelles
Highlights•A
software
suite
for
automated
analysis
of
lipid
membranes
in
electron
micrographs•Includes
segmentation,
shape
identification,
and
membrane
properties•Applied
to
datasets
with
different
lipids
protein-induced
changes•Features
an
intuitive
GUI
batch
micrograph
analysisSummaryImaging
structures
associated
protein
complexes
using
cryoelectron
microscopy
(cryo-EM)
is
a
common
visualization
structure
determination
technique.
The
quantitative
the
structures,
however,
not
routine
time
consuming
particular
when
large
amounts
data
are
involved.
Here,
we
introduce
image-processing
cryo-vesicle
image
analyzer
(CryoVIA)
that
parametrizes
from
cryo-EM
images.
This
toolkit
combines
identification
methods
automatically
perform
large-scale
local
global
properties
such
as
bilayer
thickness,
size,
curvature
including
classifications.
We
included
analyses
exemplary
compositions
changes
through
endosomal
sorting
required
transport
III
(ESCRT-III)
remodeling
protein.
opens
new
possibilities
systematically
study
structural
their
modifications
images.Graphical
abstract
Proceedings of the National Academy of Sciences,
Год журнала:
2025,
Номер
122(8)
Опубликована: Фев. 19, 2025
To
investigate
the
structure
of
mycobacterial
oxidative
phosphorylation
machinery,
we
prepared
inverted
membrane
vesicles
from
Mycobacterium
smegmatis
,
enriched
for
containing
complexes
interest,
and
imaged
with
electron
cryomicroscopy.
We
show
that
this
analysis
allows
determination
both
ATP
synthase
supercomplex
respiratory
III
IV
in
their
native
membrane.
The
latter
reveals
enzyme
malate:quinone
oxidoreductase
(Mqo)
physically
associates
supercomplex,
an
interaction
is
lost
on
extraction
proteins
lipid
bilayer.
Mqo
catalyzes
essential
reaction
Krebs
cycle,
vivo
survival
pathogens
compromised
when
its
activity
absent.
high-speed
spectroscopy
Mqo:supercomplex
enables
rapid
transfer
malate
to
supercomplex.
Further,
necessary
malate-driven,
but
not
NADH-driven,
transport
chain
oxygen
consumption.
Together,
these
findings
indicate
a
connection
between
cycle
aerobic
respiration
directs
electrons
along
single
branch
chain.