Regulation of AP-2-synaptotagmin interaction by inositol high polyphosphates.
The inositol high-polyphosphate series (IHPS) inhibits neurotransmission through binding to the second C2 domain of synaptotagmins I and II(Syt), synaptic vesicle membrane proteins. We have revealed that several proteins, including alpha adaptins which are specific subunits of clathrin assembly protein, AP2, were eluted from mouse brain by affinity elution chromatography from the C2 domains of Syt II-immobilized Sepharose using 50 microM of InsP6. The interaction between Syt II and AP2 was more markedly inhibited by IHPS than by the same concentration of InsP3. Limited digestion of mouse crude synaptosomal fractions with trypsin revealed different cleavage patterns in the presence and absence of 50 microM InsP6. These results suggest that IHPS-binding to the C2B domain of synaptotagmin alters the state of protein-protein interaction including the synaptotagmin-AP2 interaction, possibly resulting in the inhibition of events involved in the synaptic vesicle trafficking.
Mizutani
A
A
Molecular Neurobiology Laboratory, Tsukuba Life Science Center, Institute of Physical and Chemical Research (RIKEN), Ibaraki, Japan. amizutan@ims.u-tokyo.ac.jp
Fukuda
M
M
Niinobe
M
M
Mikoshiba
K
K
D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D001921:Brain / Q000378:metabolism; D002135:Calcium-Binding Proteins; D007295:Inositol Phosphates / Q000378:metabolism / Q000494:pharmacology*; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D009433:Neural Inhibition / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D009435:Synaptic Transmission / Q000187:drug effects; D050857:Synaptotagmins
D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D002135:Calcium-Binding Proteins; D007295:Inositol Phosphates; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050857:Synaptotagmins