| Modification Notes |
In all vertebrates, SV2 proteins are abundant, hydrophobic, membrane glycoproteins that are expressed as two major isoforms, SV2A and SV2B, and one minor isoform, SV2C. SV2 proteins are differentially expressed in the brain and are present on all synaptic vesicles, independent of transmitter type. While SV2A and SV2B are expressed ubiquitously througout the brain, SV2C displays a more restricted pattern of expression. SV2C is only present on a small subset of synapses in phylogenetically old brain areas, indicating that SV2C could be evolutionary more ancient than SV2A or SV2B. Specifically, SV2C is expressed in the central neuraxis, which includes the striatum, midbrain, hindbrain and the olfactory bulb. SV2C, whose molecular mass ranges due to N-glycosylation, contains cytoplasmic N-terminal and C-terminal domains. The restricted pattern of SV2C expression suggests that it may be used as a specific synaptic marker in the study of degenerative diseases, such as Parkinson’s disease. |