SV2, a Brain Synaptic Vesicle Protein Homologous to Bacterial Transporters

Abstract

Synaptic vesicle protein 2 (SV2) is a membrane glycoprotein specifically localized to secretory vesicles in neurons and endocrine cells. As a first step toward understanding the function of SV2 in neural secretion, a rat brain complementary DNA (cDNA) that encodes SV2 was isolated and characterized. Analyses of this cDNA predict that SV2 contains 12 transmembrane domains. The NH2-terminal half of the protein shows significant amino acid sequence identity to a family of bacterial proteins that transport sugars, citrate, and drugs. Expression of the SV2 cDNA in COS cells yielded a high level of SV2-like immunoreactivity distributed in a reticular and punctate pattern, which suggests localization to intracellular membranes. Its localization to vesicles, predicted membrane topology, and sequence identity to known transporters suggest that SV2 is a synaptic vesicle-specific transporter.

Synaptic Vesicle Protein SV2B, but Not SV2A, Is Predominantly Expressed and Associated with Microvesicles in Rat Pinealocytes

“…The migration pattern of the positive protein bands on the SDS gel was very similar to those previously reported (Bajjalieh et al, 1992(Bajjalieh et al, , 1993(Bajjalieh et al, , 1994. Treatment with antigenic peptides during immunodecoration abolished the immunoreactivity (Fig.…”

“…Then, 28 reaction cycles were conducted as follows: denaturation at 94°C for 30 s, annealing of the primers at the specific temperature for each set for 30 s, and then extension at 72°Cfor I mm. The sequences of the oligonucleotides used as primers were based on the following published sequences (Bajjalieh et al, 1992(Bajjalieh et al, , 1993Feany et al, 1992;Gingrich et al, 1992): SV2A-specific first sense primer, 5'-GGCAAAGGCGAACGGATGGCA-3' (bases 322-342), first antisense primer, 5 '-GATGGCAAACACAGAGGG-AAAGG-3' (bases 1,022-1,044), second sense primer, 5 '-GTGAGAGGGGGCTTAAGTGATGG-3' (bases 364-386), and second antisense primer, 5 '-CATACAGAG-CCAGCTCAAATGC-3' (bases 873-894); and SV2B specific first sense primer, 5 '-CTAAGCAGACTAAGATGG- , first antisense primer, 5 '-TCT-GGCATGAACTTCAGGGCCAC-3' (bases 874-896), second sense primer, 5 '-CCAGGCAGACCTGATGGC-TGA-3' (bases 228-248), and second antisense primer, 5 '-GCTGAGATGCTCACCGCGTTTC-3' (bases 690-711). The pairs of amplification products of SV2A and SV2B were 723 and 531, and 715 and 484 bases long for the first and second PCR, respectively.…”

“…Site-specific polyclonal antibodies against SV2A and SV2B were raised in rabbits, using synthetic peptides corresponding to the N-terminal 13 amino acids [MEEGFRDRA-AFIR(C)] of the rat SV2A sequence (Bajjalieh et al, 1992;Feany et a!., 1992;Gingrich et al, 1992), and the N-terminal 12 amino acids [MDDRYYDNYEGY (C)] of the rat SV2B sequence (Bajjalieh et al, 1993). In the case of the SV2A peptide, thyroglobulin was conjugated to the C-terminal cysteine of the peptide with m-maleimidobenzoyl-N-hydrosuccinimide ester.…”

“…Synaptic vesicle protein 2 (SV2), originally identified in cholinergic vesicles from the electric fish Discopyge ommata (Buckley and Kelly, 1985), is a glycosylated synaptic vesicle membrane protein comprising 12 transmembrane regions (Bajjalieh et al, 1992;Feany et al, 1992;Gingrich et al, 1992). Two isoforms, abbreviated as SV2A and SV2B, have been identified in mammals; the former consists of 742 amino acids and the latter of 683 amino acids, with 65% sequence homology (Bajjalieh et al, 1993(Bajjalieh et al, , 1994.…”

Synaptic Vesicle Protein 2 Binds Adenine Nucleotides

“…One of these proteins, SV2 (1), is specifically expressed in neurons and endocrine cells, where it is localized to vesicles that undergo regulated secretion. Mammalian genomes contain three isoforms of SV2 (2)(3)(4)(5), termed SV2A, SV2B, and SV2C. Of these, SV2A is the most widely expressed (6) and is the isoform whose expression is required for survival (7,8).…”