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.
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.
UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85073064889&origin=inward
UR - https://www.ncbi.nlm.nih.gov/pubmed/31594980
U2 - 10.1038/s41598-019-50684-1
DO - 10.1038/s41598-019-50684-1
M3 - Article
C2 - 31594980
VL - 9
SP - 14408
JO - Scientific Reports
JF - Scientific Reports
SN - 2045-2322
IS - 1
M1 - 14408
ER -