Synaptophysin

Takaki, M., Ujike, H., Kodama, M. et al. Increased expression of synaptophysin and stathmin mRNAs after methamphetamine administration in rat brain. Neuroreport. 12 1055, 2001. 

Synaptobrevins (VAMPs) Synaptogyrin Synaptophysins PKA but diverge C-terminally. Synapsins Ia/b contain C-terminal phosphorylation sites for CaMKII and CDK 5. Interact with microfilaments, neurofilaments, microtubules, SH3 domains, calmodulin and annexin VI in vitro. Small-membrane proteins that are cleaved by tetanus toxin and by botulinum toxins B, D, F and G. Polytopic membrane protein that is tyrosine-phosphorylated. Function unknown. Polytopic membrane proteins, including synaptoporin, that are tyrosine-phosphorylated and bind to synaptobrevins. May regulate SNARE function... 

Synaptophysin Presynaptic protein with a role in transmitter release Ubiquitin-conjugating enzymes (E2s)... 

The initial panel of antibodies described above is also useful in discriminating among small cell tumors, except that a few additional markers are needed. A panel of neuroendocrine markers (chromogranin A, synaptophysin, and CD57) should be used to differentiate neuroendocrine tumors. The use of a panel rather than just one of these markers is recommended to maximize the ability to detect poorly differentiated neuroendocrine tumors that lose the... 

In postmortem examination of tissue, the substantia nigra is readily identifiable because of the dark pigmentation in the neurons that is the result of the accumulation of neuromelanin, a substance whose neurochemical composition is not completely known but is thought to derive from oxidized dopamine. Lewy bodies are composed of many cytoskeleton and other proteins, including a-synuclein, ubiquitin, and synaptophysin. It is not clear whether the formation of these inclusions contributes to neuronal degeneration or they are merely a byproduct of degenerating neurons. 

Synaptobrevins (VAMPs)b Synaptophysins, synaptogyrin SV2 A, B, C SCAMPS 1 and 4 SVOP... 

Hannah, M. J., Weiss, U., and Huttner, W. B. 1998. Differential extraction of proteins from paraformaldehyde-fixed cells Lessons from synaptophysin and other membrane proteins. Methods Enzymol. 26 170-181. 

Fig. 3 Synaptophysin-pHluorin is a fusion construct of the synaptic vesicle protein synaptophysin (a four-transmembrane domain synaptic vesicle protein) with a pH-sensitive EGFP at its C-terminal (located in the synaptic vesicle lumen). Synaptic vesicle lumen normally has an acidic pH of approximately 5.5 at which spH fluorescence is quenched. When vesicles fuse, lumenal EGFP is exposed to the extracellular pH, which results in a marked increase in its fluorescence. During endocytosis, pHluorin fluorescence is re-quenched as vesicle lumen becomes acidic.

In addition to the proteins discussed above, neuronal SNAREs were reported to interact with numerous other proteins in a specific manner, but in most cases both the structural basis and the biological function of these interactions need to be defined. For instance, synaptophysin, a membrane protein of synaptic vesicles, forms a complex with synaptobrevin in which synaptobrevin is not available for interactions with its partner SNAREs syntaxin 1A and SNAP-25, suggesting that this complex represents a reserve pool of recruitable synaptobrevin (Becher et al. 1999) or regulates interactions between the vesicle-associated synaptobrevin and the plasmalem-mal SNAREs. Alternatively, it has been suggested that this complex is involved in synaptobrevin sorting to synaptic vesicles. 

Artalejo CR, Elhamdani A, Palfrey HC (2002) Sustained stimulation shifts the mechanism of endocytosis from dynamin-1-dependent rapid endocytosis to clathrin- and dynamin-2-mediated slow endocytosis in chromaffin cells. Proc Natl Acad Sci USA 99 6358-63 Becher A, Drenckhahn A, Pahner I, Margittai M, Jahn R, Ahnert-Hilger G (1999) The synaptophysin-synaptobrevin complex a hallmark of synaptic vesicle maturation. J Neurosd 19 1922-31... 

Bleck (1989) Clinical aspects of tetanus. In Simpson LL (ed) Botulinum neurotoxin and tetanus toxin. Academic Press, San Diego, CA, pp 379-98 Bonanomi D, Pennuto M, Rigoni M, Rossetto O, Montecucco C et al. (2005) Taipoxin induces synaptic vesicle exocytosis and disrupts the interaction of synaptophysin I with VAMP2. Mol Pharmacol 67 1901-8... 

Torri-Tarelli F, Villa A, Valtorta F et al (1990) Redistribution of synaptophysin and synapsin I during alpha-latrotoxin-induced release of neurotransmitter at the neuromuscular junction. I Cell Biol 110 449-59... 

Their proximity is established in neuroendocrine and neuronal cells, where BLOC-1 and AP-3 have been found on the same population of synaptophysin-containing vesicles (Salazar et al., 2005b, 2006). Synaptophysin is an integral membrane protein of SVLMs in PC-12 cells and of synaptic vesicles derived either from presynaptic membranes by AP-2 or from endosomes by AP-3 (cf. Salazar et al., 2004b, 2005b and Takamori et al., 2006). 

Reduced dysbindin-1 gene expression in dorsolateral prefrontal cortex (DLPFC) and hippocampal formation (HF) of schizophrenia cases studied with in situ hybridization. Asterisks in histograms indicate a significant difference between controls (darker bars) and schizophrenia cases (lighter bars). DLPFC reductions in dysbindin-1 (a) were found in all cell layers in the absence of any changes in the presynaptic marker synaptophysin (d) or the postsynaptic marker spinophilin A (g). The reductions found in the HF occurred in all areas except CA1. Graphs are accompanied by representative sections from normal (b, e, h, and k) and schizophrenia (c, f, i, and I) cases. Adapted from Weickert et al. (2004) for the DLPFC and Weickert et al. (2008) for the HF... 

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