SNARES

o SNARE mutations are mostly associated with neurological diseases as in early development the most important secreted proteins are neurotransmitters, which are vital for the correct development of the embryo.

o Most SNARE mutations occur in the C-terminal region (usually very conserved), which destabilises the structure of the SNARE

o VAMP2, a type of V-SNARE is important for neurotransmitter release. Mutations within the conserved C-terminus of the SNARE cause neurodevelopmental disorders such as, intellectual disability and autistic features. 13

SNAREs can be classified into either V-SNAREs or T-SNAREs based on their localisation [9]. V-SNAREs are located on the trafficked vesicles, whereas t-SNAREs are found on the target plasma membrane [10]. However, this method of classification is rather ambiguous as T-SNAREs can also be located on trafficking vesicles and V-SNAREs on the plasma membrane [10].

Therefore, a new classification system has been developed based on the structures of SNAREs. SNAREs can either be classified as R-SNAREs, named after the arginine residue in the centre, or Q-SNAREs, named after the glutamine (or aspartate) residue found within the SNARE complex [9]. It was discovered that the majority or V-SNAREs contained the arginine residue, however this approach helped to clear up the ambiguity created by the concept of V-SNAREs and T-SNAREs [10].

There are a few exceptions to the Q/ R classification system. One example of this is yeast Bet 1p as it contains a serine residue rather than arginine, glutamine or aspartate [9]. Another example is leech synaptobrevin as this contains a lysine residue rather than the other residue used to classify SNAREs [9]. These variations can often result in modified layer geometry