Localization of rabphilin-3A, a putative target protein for Rab3A, at the sites of Ca(2+)-dependent exocytosis in PC12 cells.
Rab3A/Smg 25A, a small GTP-binding protein, is highly concentrated in presynapse of neurons and implicated in neurotransmitter release. We have recently identified a putative target protein for Rab3A, isolated its cDNA, and designated it as Rabphilin-3A. To examine whether Rabphilin-3A as well as Rab3A is localized at the sites of Ca(2+)-dependent exocytosis, we investigated here localization of Rabphilin-3A and Rab3A in comparison with the sites of exocytosis in the differentiated PC12 cells. Rabphilin-3A as well as Rab3A was highly concentrated at the tips of the neurites where Ca(2+)-dependent exocytosis took place. Inversely, neither Rabphilin-3A nor Rab3A was concentrated at the tips of the neurites where Ca(2+)-dependent exocytosis did not take place. These results suggest that Rabphilin-3A as well as Rab3A constitutes a part of the machinery necessary for neurotransmitter release.
Wada
K
K
Department of Biochemistry, Kobe University School of Medicine, Japan.
Mizoguchi
A
A
Kaibuchi
K
K
Shirataki
H
H
Ide
C
C
Takai
Y
Y
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000911:Antibodies, Monoclonal; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D005089:Exocytosis; D005455:Fluorescent Antibody Technique; D019204:GTP-Binding Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D015151:Immunoblotting; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D016716:PC12 Cells; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins; D000097624:Rabphilin-3A
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D003994:Bucladesine; D002118:Calcium; D019204:GTP-Binding Proteins; D009419:Nerve Tissue Proteins; D033921:Vesicular Transport Proteins; D020691:rab GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins; D000097624:Rabphilin-3A