Related Experiment Video
Updated: May 13, 2026

Dissecting Cell-Autonomous Function of Fragile X Mental Retardation Protein in an Auditory Circuit by In Ovo Electroporation
Published on: July 6, 2022
FMRP regulates neurotransmitter release and synaptic information transmission by modulating action potential duration
Pan-Yue Deng1, Ziv Rotman, Jay A Blundon
1Departments of Biomedical Engineering and Cell Biology and Physiology, CIMED, Washington University, St. Louis, MO 63110, USA.
Abstract:
Loss of FMRP causes fragile X syndrome (FXS), but the physiological functions of FMRP remain highly debatable. Here we show that FMRP regulates neurotransmitter release in CA3 pyramidal neurons by modulating action potential (AP) duration. Loss of FMRP leads to excessive AP broadening during repetitive activity, enhanced presynaptic calcium influx, and elevated neurotransmitter release. The AP broadening defects caused by FMRP loss have a cell-autonomous presynaptic origin and can be acutely rescued in postnatal neurons. These presynaptic actions of FMRP are translation independent and are mediated selectively by BK channels via interaction of FMRP with BK channel's regulatory β4 subunits. Information-theoretical analysis demonstrates that loss of these FMRP functions causes marked dysregulation of synaptic information transmission. FMRP-dependent AP broadening is not limited to the hippocampus, but also occurs in cortical pyramidal neurons. Our results thus suggest major translation-independent presynaptic functions of FMRP that may have important implications for understanding FXS neuropathology.
Related Concept Videos
Neurochemical Transmission: Sites of Drug Action
Excitatory and Inhibitory Effects of Neurotransmitters
Postsynaptic Potential (PSP)
There are two types of receptors: ionotropic and metabotropic.
The ionotropic receptor is the membrane protein that has an...
Ligand-Gated Ion Channel Receptor: Gating Mechanism
G-Protein Gated Ion Channels
Sensory organs,...
Chemical Synapses
Because chemical synapses depend on the release of neurotransmitter molecules from synaptic vesicles to pass on their signal, there is an approximately one millisecond delay between when the axon potential reaches the presynaptic terminal and when the neurotransmitter leads to opening of postsynaptic ion channels. Additionally, this signaling is...

