Phosphorylation of 46-kappa Da protein of synaptic vesicle membranes is stimulated by GTP and Ca2+/calmodulin
Experimental & Molecular Medicine
;
: 434-443, 2002.
Article
in English
| WPRIM
| ID: wpr-13045
ABSTRACT
The release of neurotransmitter is regulated in the processes of membrane docking and membrane fusion between synaptic vesicles and presynaptic plasma membranes. Synaptic vesicles contain a diverse set of proteins that participate in these processes. Small GTP-binding proteins exist in the synaptic vesicles and are suggested to play roles for the regulation of neurotransmitter release. We have examined a possible role of GTP-binding proteins in the regulation of protein phosphorylation in the synaptic vesicles. GTPgammaS stimulated the phosphorylation of 46 kappa Da protein (p46) with pI value of 5.0-5.2, but GDPbetaS did not. The p46 was identified as protein interacting with C-kinase 1 (PICK-1) by MALDI-TOF mass spectroscopy analysis, and anti-PICK-1 antibody recognized the p46 spot on 2-dimensional gel electrophoresis. Rab guanine nucleotide dissociation inhibitor (RabGDI), which dissociates Rab proteins from SVs, did not affect phosphorylation of p46. Ca2+/ calmodulin (CaM), which causes the small GTP- binding proteins like Rab3A and RalA to dissociate from the membranes and stimulates CaM- dependnet protein kinase(s) and phosphatase, strongly stimulate the phosphorylation of p46 in the presence of cyclosporin A and cyclophylin. However, RhoGDI, which dissociates Rho proteins from membranes, reduced the phosphorylation of p46 to the extent of about 50%. These results support that p46 was PICK-1, and its phosphorylation was stimulated by GTP and Ca2+/CaM directly or indirectly through GTP-binding protein(s) and Ca2+/CaM effector protein(s). The phosphorylation of p46 (PICK-1) by GTP and Ca2+/CaM may be important for the regulation of transporters and neurosecretion.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Phosphorylation
/
Synaptic Membranes
/
Synaptic Vesicles
/
Recombinant Fusion Proteins
/
Calmodulin
/
Carrier Proteins
/
Calcium
/
Monomeric GTP-Binding Proteins
/
Guanine Nucleotide Dissociation Inhibitors
/
Guanosine Triphosphate
Type of study:
Prognostic study
Limits:
Animals
Language:
English
Journal:
Experimental & Molecular Medicine
Year:
2002
Type:
Article
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