Characterization of the interaction between synapsin I and calspectin (brain spectrin or fodrin).
We characterized the properties of the interaction between synapsin I and calspectin using purified proteins. The binding assay in the native state using antibodies specific to the tail region of synapsin I revealed that the binding is a high affinity with Kd of 9 nM, which is almost comparable to that of synapsin I to synaptic vesicles and to F-actin. We demonstrated that the head-middle region of synapsin I binds the NH2-terminal domain of beta subunit of calspectin, which also contains an actin binding site. Furthermore, the interaction was significantly inhibited by phosphorylation of synapsin I by cAMP-dependent protein kinase or by Ca2+, calmodulin-dependent protein kinase II. These properties of the interaction between synapsin I and calspectin may help understanding of its modulatory roles in neurotransmitter release.
Iga
M
M
Department of Neurochemistry and Neuropharmacology, Biomedical Research Center, Osaka University Medical School, Japan.
Inui
M
M
Sobue
K
K
D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000737:chemistry*; D002352:Carrier Proteins / Q000737:chemistry; D002417:Cattle; D002540:Cerebral Cortex / Q000737:chemistry; D008840:Microfilament Proteins / Q000737:chemistry; D009419:Nerve Tissue Proteins / Q000737:chemistry; D010750:Phosphoproteins / Q000737:chemistry; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D013329:Structure-Activity Relationship; D016704:Synapsins / Q000737:chemistry*; D013049:Spectrin
D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D016704:Synapsins; D013049:Spectrin