Sortin-Nexin
4
(SNX4)
is
an
evolutionary
conserved
organizer
of
membrane
recycling.
In
neurons,
SNX4
accumulates
in
synapses,
but
how
affects
synapse
function
remains
unknown.
We
generated
a
conditional
knock-out
mouse
model
and
report
that
cKO
synapses
show
enhanced
neurotransmission
during
train
stimulation,
while
the
first
evoked
EPSC
was
normal.
depletion
did
not
affect
vesicle
recycling
or
levels
localization
SNARE-protein
VAMP2/synaptobrevin-2.
However,
affected
ultrastructure:
increase
docked
synaptic
vesicles
at
active
zone,
overall
number
normal,
decreased
zone
length.
These
effects
together
lead
to
substantially
increased
density
per
release
site.
conclusion,
negative
regulator
docking
release.
findings
suggest
role
for
recruitment
zone.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2023,
Номер
unknown
Опубликована: Окт. 30, 2023
SUMMARY
Building
synaptic
connections,
which
are
often
far
from
the
soma,
requires
coordinating
a
host
of
cellular
activities
transcription
to
protein
turnover,
placing
high
demand
on
intracellular
communication.
Membrane
contact
sites
(MCSs)
formed
between
organelles
have
emerged
as
key
signaling
hubs
for
an
array
activities.
We
found
that
endoplasmic
reticulum
(ER)
MCS
tethering
PDZD8
is
required
activity-dependent
synaptogenesis.
sufficient
drive
ectopic
bouton
formation
through
autophagy-dependent
mechanism
and
basal
synapse
when
autophagy
biogenesis
limited.
functions
at
ER-late
endosome/lysosome
(LEL)
MCSs
promote
lysosome
maturation
accelerate
autophagic
flux.
Mutational
analysis
PDZD8’s
SMP
domain
further
suggests
role
lipid
transfer
ER-LEL
MCSs.
propose
PDZD8-dependent
ER
LELs
promotes
increase
flux
during
periods
demand,
including
formation.
GRAPHICAL
ABSTRACT
The Journal of Cell Biology,
Год журнала:
2024,
Номер
224(2)
Опубликована: Дек. 24, 2024
Synaptic
dysfunction
is
one
of
the
earliest
cellular
defects
observed
in
Alzheimer's
disease
(AD)
and
Parkinson's
(PD),
occurring
before
widespread
protein
aggregation,
neuronal
loss,
cognitive
decline.
While
field
has
focused
on
aggregation
Tau
α-Synuclein
(α-Syn),
emerging
evidence
suggests
that
these
proteins
may
drive
presynaptic
pathology
even
their
aggregation.
Therefore,
understanding
mechanisms
by
which
α-Syn
affect
terminals
offers
an
opportunity
for
developing
innovative
therapeutics
aimed
at
preserving
synapses
potentially
halting
neurodegeneration.
This
review
focuses
molecular
converge
caused
α-Syn.
Both
have
physiological
roles
synapses.
However,
during
disease,
they
acquire
abnormal
functions
due
to
aberrant
interactions
mislocalization.
We
provide
overview
current
research
different
essential
pathways
influenced
Finally,
we
highlight
promising
therapeutic
targets
maintaining
synaptic
function
both
tauopathies
synucleinopathies.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 4, 2024
Abstract
Autophagy
is
a
vital
catabolic
process
responsible
for
the
degradation
of
cytosolic
components,
playing
key
role
in
cellular
homeostasis
and
survival.
At
synapses,
autophagy
crucial
regulating
neuronal
activity
utilizes
specialized
machinery.
While
considerable
progress
has
been
made
understanding
initiation
autophagosome
formation,
mechanisms
governing
clearance
autophagosomes
from
synaptic
sites
remain
poorly
understood.
Here,
we
identify
novel
pathway
which
astrocytes
actively
participate
pre-synaptic
autophagosomes.
Using
neurons
derived
human
induced
pluripotent
stem
cell
(hiPSC)
lines
expressing
fluorescent
markers
chimeric
mouse
models,
demonstrate
that
autophagosomal
vesicles
are
physically
transferred
to
astrocytes,
enhanced
when
suppressed.
Autophagosome
transfer
does
not
require
direct
physical
contact,
but
it
Dynamin
cholesterol-dependent
endocytosis
internalized
ultimately
fuse
with
astrocytic
lysosomes.
Our
findings
reveal
previously
unrecognized
mechanism
slow
axonal
retrograde
transport
their
nearby
astrocytes.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 21, 2024
Presynaptic
terminals
can
be
located
far
from
the
neuronal
cell
body
and
are
thought
to
independently
regulate
protein
organelle
turnover.
In
this
work,
we
report
a
soma-centered
mechanism
that
regulates
autophagy-driven
turnover
at
distant
presynaptic
in
Drosophila.
We
show
system
is
regulated
by
Rab39,
whose
human
homolog
mutated
Parkinson's
disease.
Although
Rab39
localized
soma,
its
loss
of
function
causes
increased
autophagy
terminals,
resulting
faster
synaptic
neurodegeneration.
Using
large-scale
unbiased
genetic
modifier
screen,
identified
genes
encoding
cytoskeletal
axonal
organizing
proteins,
including
Shortstop
(Shot),
as
suppressors
autophagy.
demonstrate
controls
Shot-
Unc104/KIF1a-mediated
transport
autophagy-related
Atg9
vesicles
synapses.
Under
starvation
conditions,
soma
shifts
localization
endosomes
lysosomes,
thereby
controlling
availability
for
trafficking
Our
findings
indicate
Rab39-mediated
orchestrates
cross-compartmental
abundance
Sorting
nexin
4
(SNX4)
is
an
evolutionary
conserved
organizer
of
membrane
recycling.
In
neurons,
SNX4
accumulates
in
synapses,
but
how
affects
synapse
function
remains
unknown.
We
generated
a
conditional
knock-out
mouse
model
and
report
that
cKO
synapses
show
enhanced
neurotransmission
during
train
stimulation,
while
the
first
evoked
EPSC
was
normal.
depletion
did
not
affect
vesicle
recycling,
basic
autophagic
flux,
or
levels
localization
SNARE-protein
VAMP2/synaptobrevin-2.
However,
affected
ultrastructure:
increase
docked
synaptic
vesicles
at
active
zone,
overall
number
normal,
decreased
zone
length.
These
effects
together
lead
to
substantially
increased
density
per
release
site.
conclusion,
negative
regulator
docking
release.
findings
suggest
role
for
recruitment
zone.
bioRxiv (Cold Spring Harbor Laboratory),
Год журнала:
2022,
Номер
unknown
Опубликована: Фев. 11, 2022
Abstract
Autophagy
provides
nutrients
during
starvation
and
eliminates
detrimental
cellular
components.
However,
accumulating
evidence
indicates
that
autophagy
is
not
merely
a
housekeeping
process.
Here,
we
show
the
protein
AuTophaGy
5
(ATG5)
functions
in
neurons
to
regulate
cAMP-dependent
kinase
A
(PKA)-mediated
phosphorylation
of
synapse-confined
proteome.
This
function
ATG5
independent
bulk
turnover
synaptic
proteins
requires
targeting
PKA
inhibitory
R1
subunits
autophagosomes.
Neuronal
loss
causes
accumulation
R1,
which
sequesters
catalytic
subunit
diminishes
cAMP/PKA-dependent
postsynaptic
cytoskeletal
mediating
AMPAR
trafficking.
Glutamatergic
neurons-confined
deletion
augments
AMPAR-dependent
excitatory
neurotransmission
appearance
spontaneous
recurrent
seizures
mice.
Our
findings
identify
novel
role
regulating
signaling
at
glutamatergic
synapses
suggest
as
target
for
restoration
neurodegenerative
conditions
with
dysfunction.