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.
Hepp
R
R
INSERM Unité 338, Biologie de la Communication Cellulaire, Strasbourg, France. hepp@neurochem.u-strasbg.fr
Perraut
M
M
Chasserot-Golaz
S
S
Galli
T
T
Aunis
D
D
Langley
K
K
Grant
N J
NJ
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