Cultured glial cells express the SNAP-25 analogue SNAP-23.
Astrocytes release glutamate and aspartate in response to elevated intracellular calcium levels, and it has been proposed that this occurs by a vesicular release mechanism, in which SNARE proteins are implicated. Although syntaxin, synaptobrevin, and cellubrevin have been shown to be expressed by cultured astrocytes, SNAP-25 has not been detected. By using immunocytochemical, immunoblotting, and polymerase chain reaction techniques, the present study demonstrates that SNAP-23, an analogue of SNAP-25, is expressed by astrocytes both in culture and in rat cerebellum. These findings provide additional evidence that astrocytes release excitatory amino acids by a vesicular mechanism involving SNARE proteins. SNAP-23 and also syntaxin 1 and cellubrevin were found to be expressed in glial precursor cells, oligodendrocytes, and microglia. These data suggest that the t-SNAREs SNAP-23 and syntaxin 1 and the v-SNARE cellubrevin participate in general membrane insertion mechanisms involved in diverse glial cell functions such as secretion, phagocytosis, and myelinogenesis.
INSERM Unité 338, Biologie de la Communication Cellulaire, Strasbourg, France. hepp@neurochem.u-strasbg.fr
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Hepp
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Perraut
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Chasserot-Golaz
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Galli
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Aunis
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Langley
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Grant
D000818:Animals; D000831:Animals, Newborn; D000954:Antigens, Surface / Q000096:biosynthesis* / Q000235:genetics; D001253:Astrocytes / Q000378:metabolism; D015153:Blotting, Western; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002462:Cell Membrane / Q000378:metabolism / Q000502:physiology; D002478:Cells, Cultured; D019084:Fluorescent Antibody Technique, Indirect; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D017628:Microglia / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis* / Q000235:genetics; D009457:Neuroglia / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D051381:Rats; D017208:Rats, Wistar; D013234:Stem Cells / Q000378:metabolism; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1; D051040:Vesicle-Associated Membrane Protein 3
D000954:Antigens, Surface; D002352:Carrier Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; C100493:SNAP23 protein, human; C494212:STX1A protein, human; C494210:Snap25 protein, rat; C494213:Stx1a protein, rat; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1; D051040:Vesicle-Associated Membrane Protein 3