About SNAP / Synaptosomal Associated Protein:
Synaptosomal-Associated Protein, 25kDa (SNAP-25) is one of the SNARE proteins and forms part of the trans-SNARE complex. As such, its main function is to govern vesicle fusion. This is mainly, although not uniquely, through exocytosis.
The primary function of SNAP-25 is to regulate the fusion of vesicles with the target membrane. It also plays a role in synaptogenesis, neuronal plasticity, postsynaptic receptor trafficking, and spine morphogenesis and density.
SNAP-25 also influences non-neural processes including metabolism. Issues with SNAP-25 are linked with several neurodevelopmental disorders. These include attention deficit hyperactivity disorder (ADHD), schizophrenia, Alzheimer's disease, bipolar disorder, epilepsy, and neuroticism. It is linked with neonatal development and learning disabilities.
Synaptosomal Associated Protein Structure
The SNAP-25 gene is located in position 12.2 of the p arm of chromosome 20 (20p12.2). It has 10 exons. The SNAP-25 protein is a 25 kDa protein. It consists of 206 amino acids.
The SNAP-25 protein is divided into two forms. These are SNAP25a and SNAP25b. Both are structured as an N-terminal α-helix, a random coil linker region with four cysteines, and a C-terminal α-helix. In SNAP25a, the four cysteines are clustered towards the center. In SNAP25b the four cysteines are clustered towards the C-terminus.
SNAP25a is diffuse whereas SNAP25b is only located in terminals and varicosities.
Currently, SNAP-25 is known to have 13 interactions. These are:
Synaptotagmin (in the presence of Ca2+)
Synaptosomal Associated Protein Mechanism of action
SNAP-25 forms a tight complex that bonds the synaptic vesicle and plasma membranes.