Super-resolution spatial, temporal and functional characterisation of voltage-gated calcium channels involved in exocytosis
Abstract
The
process
of
information
transfer
between
neurons
or
endocrine
cells
is
one
of
the
most
important,
intricate
and
temporally
precise
processes
in
the
body.
Exocytosis,
which
is
central
to
the
process
of
excitation-‐secretion
coupling,
is
triggered
by
calcium
signalling
through
voltage-‐gated
calcium
channels.
Super-‐resolution
imaging
offers
the
possibility
to
fully
understand
the
spatial
relationship
between
the
SNARE
proteins
involved
in
exocytosis,
vesicles
and
the
associated
voltage-‐gated
calcium
channels.
In
this
thesis
the
focus
is
on
exploring
the
trigger
for
exocytosis,
specifically
the
spatial
and
functional
role
that
voltage-‐gated
calcium
channels
play
in
this
process.
Super-‐
resolution
imaging
techniques
have
been
applied
to
measure
the
interaction
between
Cav2.2
calcium
channels
and
the
syntaxin1a
SNARE
protein,
where
binding
was
found
to
affect
the
overall
channel
distribution.
A
novel
method
of
caged
dye
conjugated
ω-‐
conotoxin
GVIA
binding
was
developed
for
live
cell
single
molecule
imaging
of
Cav2.2
calcium
channels.
An
innovative
approach
to
analyse
channel
functionality
and
the
distribution
of
calcium
events
at
the
plasma
membrane
was
developed
to
create
a
temporal-‐spatial
map
of
calcium
activity
across
the
cell.
These
developments,
combined
with
newly
developed
techniques
in
optical
patching
and
simultaneous
calcium
and
vesicle
imaging
reveal
the
functional
relationship
of
voltage-‐gated
calcium
channel
and
exocytosis
at
unprecedented
spatial
and
temporal
scales.