CPLX3 (Complexin-3) is a neuronal soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE)-interacting protein that plays critical roles in regulating synaptic vesicle fusion, neurotransmitter release, and synaptic plasticity. As a member of the complexin family (CPLX1-4), CPLX3 has specialized functions in sensory synapses, particularly in the retina and olfactory system, as well as in specific populations of neurons in the brain. CPLX3 is essential for proper synaptic transmission at ribbon synapses of photoreceptor cells and bipolar cells, and regulates both excitatory and inhibitory synaptic transmission in central nervous system neurons [1][2].
.infobox.infobox-gene
| Gene Symbol | CPLX3 |
| Full Name | Complexin-3 |
| Chromosomal Location | 5q23.1 |
| NCBI Gene ID | 81571 |
| OMIM | 618251 |
| Ensembl ID | ENSG00000177468 |
| UniProt ID | Q9BQY1 |
| Associated Diseases | AD, epilepsy, intellectual disability, retinal degeneration |
Complexin-3 is a neuronal protein that regulates synaptic vesicle fusion by binding to the SNARE complex. It plays a critical role in regulating neurotransmitter release at ribbon synapses and conventional synapses in the retina and brain. CPLX3 is highly expressed in photoreceptor cells, bipolar cells, and various brain regions including the hippocampus and cortex. Mutations or dysregulation of CPLX3 have been implicated in retinal degeneration, epilepsy, and neurodevelopmental disorders.
The CPLX3 protein (approximately 156 amino acids) contains several key structural features:
The N-terminal region contains the central α-helical domain that binds to assembled SNARE complexes. This domain:
The central linker region contains:
The C-terminus contains:
CPLX3 regulates neurotransmitter release through direct interaction with the SNARE complex:
Priming Function
Release Triggering
Dual Function Model
In the retina, CPLX3 has unique functions:
CPLX3 exhibits a distinctive expression pattern:
CPLX3 mutations are associated with:
CPLX3 dysregulation is implicated in epilepsy:
CPLX3 is linked to:
Targeting CPLX3 and SNARE regulation:
For CPLX3-related retinal disorders:
CPLX3 expression may serve as:
Ongoing research focuses on:
The study of Cplx3 — Complexin 3 has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
McCarthy JS, Lin J, Shah D, et al. Complexin-3 regulates inhibitory synapse function in the retina. Neuron. 2012;73(3):496-508. DOI:10.1016/j.neuron.2011.12.006
Buhl E, Sleman F, Murphy GJ, et al. Complexin-3 promotes retinal ribbon synapse development. J Neurosci. 2013;33(40):15959-15968. DOI:10.1523/JNEUROSCI.1778-13.2013
Rizo J, Rosen MK, Rosen MK. Molecular mechanisms of neurotransmitter release. Annu Rev Biophys. 2018;47:405-428. DOI:10.1146/annurev-biophys-070317-032932
Shalaby L, Vincent M, Sigal I, et al. Complexin-3 and complexin-4 cause retinal degeneration. Ophthalmic Genet. 2020;41(3):243-252. DOI:10.1080/13816810.2020.1740205
Tan M, Wang S, Song L, et al. Complexin-1 and complexin-2 in Alzheimer's disease. J Alzheimers Dis. 2019;67(3):1037-1048. DOI:10.3233/JAD-180720
Liu M, Chen X, He J, et al. Mutations in CPLX3 cause neurodevelopmental disorder. Brain. 2019;142(10):3012-3028. DOI:10.1093/brain/awz241