Synaptic vesicles represent specialized secretory organelles that store neurotransmitters in nerve terminals, and release them by fusing with the presynaptic plasma membrane during exocytosis. Synaptogyrin (SYNGR1) and synaptophysins I and II (synaptoporin) contain 4 transmembrane regions with cytoplasmic C and N termini, and are among the most abundant synaptic vesicle proteins.For a description of the synaptogyrin family, which includes SYNGR4.By genomic sequence analysis, Smith et al. (2000) identified SYNGR4 within a 1.6-Mb glioma tumor suppressor region on chromosome 19q. The SYNGR4 protein contains 234 amino acids.Smith et al. (2000) determined that the SYNGR4 gene contains 4 exons.By genomic sequence analysis, Smith et al. (2000) mapped the SYNGR4 gene to chromosome 19q13.3.