Phosphorylated synaphin/complexin found in the brain exhibits enhanced SNARE complex binding.
The cytosolic protein synaphin/complexin critically regulates fast neurotransmitter release at the synapse by binding to SNARE complex. However, the exact mechanism of its action remains unclear, and very little is known about how it is physiologically regulated. Here we show that synaphins (Syps) 1 and 2 can be phosphorylated in vitro by protein kinase CK2 (CK2). The only phosphorylation site by CK2 was serine-115 (Ser-115) of Syps 1 and 2. Syps 1 and 2 exhibited higher affinities to native and recombinant SNARE complexes when phosphorylated at Ser-115. We found Ser-115-phosphorylated Syp 1 (pS115-Syp 1) in the cytosolic fraction of the rat brain using polyclonal antibody specific to pS115-Syps 1 and 2. These results suggest that the activity of Syp is regulated by CK2 phosphorylation of its Ser-115 in vivo. The phosphorylation may provide a new route for modulating fast neurotransmitter release.
Shata
Atsushi
A
Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan.
Saisu
Hideo
H
Odani
Shoji
S
Abe
Teruo
T
D033942:Adaptor Proteins, Vesicular Transport; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D051381:Rats; D050600:SNARE Proteins / Q000737:chemistry / Q000378:metabolism*; D012694:Serine / Q000737:chemistry / Q000235:genetics
D033942:Adaptor Proteins, Vesicular Transport; D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D050600:SNARE Proteins; C095993:complexin II; D012694:Serine