TY - JOUR
T1 - Doc2b Ca2+ binding site mutants enhance synaptic release at rest at the expense of sustained synaptic strength
AU - Bourgeois-Jaarsma, Quentin
AU - Verhage, Matthijs
AU - Groffen, Alexander J.
N1 - Funding Information: We thank Robbert Zalm, Desiree Schut, Joke Wortel, Joost Hoetjes, Ingrid Saarloos and Eline Kompanje for excellent technical support. We express gratitude to Vincent Huson, Javier Emerador Melero, Rocio Diez Arazola and members of CNCR lab for their critical and their scientific support. This study was financially supported by the EU in the European Neuroscience Campus Network (Cycle 4, project 3) and the Netherlands Organization for Health Research and Development (ZonMW project 91113022). Publisher Copyright: © 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Communication between neurons involves presynaptic neurotransmitter release which can be evoked by action potentials or occur spontaneously as a result of stochastic vesicle fusion. The Ca2+-binding double C2 proteins Doc2a and –b were implicated in spontaneous and asynchronous evoked release, but the mechanism remains unclear. Here, we compared wildtype Doc2b with two Ca2+ binding site mutants named DN and 6A, previously classified as gain- and loss-of-function mutants. They carry the substitutions D218,220N or D163,218,220,303,357,359A respectively. We found that both mutants bound phospholipids at low Ca2+ concentrations and were membrane-associated in resting neurons, thus mimicking a Ca2+-activated state. Their overexpression in hippocampal primary cultured neurons had similar effects on spontaneous and evoked release, inducing high mEPSC frequencies and increased short-term depression. Together, these data suggest that the DN and 6A mutants both act as gain-of-function mutants at resting conditions.
AB - Communication between neurons involves presynaptic neurotransmitter release which can be evoked by action potentials or occur spontaneously as a result of stochastic vesicle fusion. The Ca2+-binding double C2 proteins Doc2a and –b were implicated in spontaneous and asynchronous evoked release, but the mechanism remains unclear. Here, we compared wildtype Doc2b with two Ca2+ binding site mutants named DN and 6A, previously classified as gain- and loss-of-function mutants. They carry the substitutions D218,220N or D163,218,220,303,357,359A respectively. We found that both mutants bound phospholipids at low Ca2+ concentrations and were membrane-associated in resting neurons, thus mimicking a Ca2+-activated state. Their overexpression in hippocampal primary cultured neurons had similar effects on spontaneous and evoked release, inducing high mEPSC frequencies and increased short-term depression. Together, these data suggest that the DN and 6A mutants both act as gain-of-function mutants at resting conditions.
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UR - https://www.ncbi.nlm.nih.gov/pubmed/31594980
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U2 - https://doi.org/10.1038/s41598-019-50684-1
DO - https://doi.org/10.1038/s41598-019-50684-1
M3 - Article
C2 - 31594980
SN - 2045-2322
VL - 9
SP - 14408
JO - Scientific reports
JF - Scientific reports
IS - 1
M1 - 14408
ER -