Bsn
Function
Scaffold protein of the presynaptic cytomatrix at the active zone (CAZ) which is the place in the synapse where neurotransmitter is released (PubMed:12628168, PubMed:12628169, PubMed:19812333). After synthesis, participates in the formation of Golgi-derived membranous organelles termed Piccolo-Bassoon transport vesicles (PTVs) that are transported along axons to sites of nascent synaptic contacts (By similarity). At the presynaptic active zone, regulates the spatial organization of synaptic vesicle cluster, the protein complexes that execute membrane fusion and compensatory endocytosis (By similarity). Functions also in processes other than assembly such as the regulation of specific presynaptic protein ubiquitination by interacting with SIAH1 or the regulation of presynaptic autophagy by associating with ATG5 (By similarity) (PubMed:28231469). Mediates also synapse to nucleus communication leading to reconfiguration of gene expression by associating with the transcriptional corepressor CTBP1 and by subsequently reducing the size of its pool available for nuclear import (By similarity). Inhibits the activity of the proportion of DAO enzyme that localizes to the presynaptic active zone, which may modulate synaptic transmission (By similarity).
Post-translational modifications
Myristoylated. The N-terminal myristoylation is not sufficient for presynaptic localization (By similarity).
Tissue Specificity
Expressed in brain and retina.
Cellular localization
- Cytoplasm
- Presynaptic active zone
- Cytoplasm
- Cytoskeleton
- Cytoplasmic vesicle
- Secretory vesicle
- Synaptic vesicle membrane
- Peripheral membrane protein
- In retina, is localized in the outer plexiform layer at ribbon synapses formed by rods and cones but was absent from basal synaptic contacts formed by cones. In the retinal inner plexiform layer localized to conventional inhibitory GABAergic synapses, made by amacrine cells, but absent from the bipolar cell ribbon synapses (By similarity).
Alternative names
Kiaa0434, Bsn, Protein bassoon