Journal article
Distinct roles of Drosophila cacophony and Dmca1D Ca2+ channels in synaptic homeostasis: Genetic interactions with slowpoke Ca2+-activated BK channels in presynaptic excitability and postsynaptic response
Developmental neurobiology (Hoboken, N.J.), Vol.74(1), pp.1-15
01/2014
DOI: 10.1002/dneu.22120
PMCID: PMC3859705
PMID: 23959639
Abstract
Ca
2+
influx through voltage-activated Ca
2+
channels and its feedback regulation by Ca
2+
-activated K
+
(BK) channels is critical in Ca
2+
-dependent cellular processes, including synaptic transmission, growth and homeostasis. Here we report differential roles of
cacophony
(Ca
V
2) and
Dmca1D
(Ca
V
1) Ca
2+
channels in synaptic transmission and in synaptic homeostatic regulations induced by
slowpoke
(
slo
) BK channel mutations. At
Drosophila
larval neuromuscular junctions (NMJs), a well-established homeostatic mechanism of transmitter release enhancement is triggered by experimentally suppressing postsynaptic receptor response. In contrast, a distinct homeostatic adjustment is induced by
slo
mutations. To compensate for the loss of BK channel control presynaptic Sh K
+
current is upregulated to suppress transmitter release, coupled with a reduction in quantal size. We demonstrate contrasting effects of
cac
and
Dmca1D
channels in decreasing transmitter release and muscle excitability, respectively, consistent with their predominant pre- vs. post-synaptic localization. Antibody staining indicated reduced postsynaptic GluRII receptor subunit density and altered ratio of GluRII A and B subunits in
slo
NMJs, leading to quantal size reduction. Such
slo
-triggered modifications were suppressed in
cac;;slo
larvae, correlated with a quantal size reversion to normal in double mutants, indicating a role of
cac
Ca
2+
channels in
slo
-triggered homeostatic processes. In
Dmca1D;slo
double mutants, the quantal size and quantal content were not drastically different from those of
slo
, although
Dmca1D
suppressed the
slo
-induced satellite bouton overgrowth. Taken together,
cac
and
Dmca1D
Ca
2+
channels differentially contribute to functional and structural aspects of
slo
-induced synaptic modifications.
Details
- Title: Subtitle
- Distinct roles of Drosophila cacophony and Dmca1D Ca2+ channels in synaptic homeostasis: Genetic interactions with slowpoke Ca2+-activated BK channels in presynaptic excitability and postsynaptic response
- Creators
- Jihye Lee - Interdisciplinary Program in Neuroscience, The University of Iowa, Iowa City, IA 52242, USAAtsushi Ueda - Department of Biology, The University of Iowa, Iowa City, IA 52242, USAChun-Fang Wu - Interdisciplinary Program in Neuroscience, The University of Iowa, Iowa City, IA 52242, USA
- Resource Type
- Journal article
- Publication Details
- Developmental neurobiology (Hoboken, N.J.), Vol.74(1), pp.1-15
- DOI
- 10.1002/dneu.22120
- PMID
- 23959639
- PMCID
- PMC3859705
- NLM abbreviation
- Dev Neurobiol
- ISSN
- 1932-8451
- eISSN
- 1932-846X
- Grant note
- R01 NS026528 || NS / National Institute of Neurological Disorders and Stroke : NINDS R01 GM088804 || GM / National Institute of General Medical Sciences : NIGMS
- Language
- English
- Date published
- 01/2014
- Academic Unit
- Iowa Neuroscience Institute; Biology
- Record Identifier
- 9984070767402771
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