TY - JOUR
T1 - Specificity of the binding of synapsin I to Src homology 3 domains
AU - Onofri, Franco
AU - Giovedì, Silvia
AU - Kao, Hung Teh
AU - Valtorta, Flavia
AU - Borbone, Lucilla Bongiorno
AU - De Camilli, Pietro
AU - Greengard, Paul
AU - Benfenati, Fabio
PY - 2000/9/22
Y1 - 2000/9/22
N2 - Synapsins are synaptic vesicle-associated phosphoproteins involved in synapse formation and regulation of neurotransmitter release. Recently, synapsin I has been found to bind the Src homology 3 (SH3) domains of Grb2 and c-Src. In this work we have analyzed the interactions between synapsins and an array of SH3 domains belonging to proteins involved in signal transduction, cytoskeleton assembly, or endocytosis. The binding of synapsin I was specific for a subset of SH3 domains. The highest binding was observed with SH3 domains of c-Src, phospholipase C-γ, p85 subunit of phosphatidyl-inositol 3-kinase, full-length and NH2-terminal Grb2, whereas binding was moderate with the SH3 domains of amphiphysins I/II, Crk, α-spectrin, and NADPH oxidase factor p47phox and negligible with the SH3 domains of p21ras GTPase-activating protein and COOH-terminal Grb2. Distinct sites in the proline-rich COOH-terminal region of synapsin I were found to be involved in binding to the various SH3 domains. Synapsin II also interacted with SH3 domains with a partly distinct binding pattern. Phosphorylation of synapsin I in the COOH-terminal region by Ca2+/calmodulin-dependent protein kinase II or mitogen-activated protein kinase modulated the binding to the SH3 domains of amphiphysins I/II, Crk, and α-spectrin without affecting the high affinity interactions. The SH3-mediated interaction of synapsin I with amphiphysins affected the ability of synapsin I to interact with actin and synaptic vesicles, and pools of synapsin I and amphiphysin I were shown to associate in isolated nerve terminals. The ability to bind multiple SH3 domains further implicates the synapsins in signal transduction and protein-protein interactions at the nerve terminal level.
AB - Synapsins are synaptic vesicle-associated phosphoproteins involved in synapse formation and regulation of neurotransmitter release. Recently, synapsin I has been found to bind the Src homology 3 (SH3) domains of Grb2 and c-Src. In this work we have analyzed the interactions between synapsins and an array of SH3 domains belonging to proteins involved in signal transduction, cytoskeleton assembly, or endocytosis. The binding of synapsin I was specific for a subset of SH3 domains. The highest binding was observed with SH3 domains of c-Src, phospholipase C-γ, p85 subunit of phosphatidyl-inositol 3-kinase, full-length and NH2-terminal Grb2, whereas binding was moderate with the SH3 domains of amphiphysins I/II, Crk, α-spectrin, and NADPH oxidase factor p47phox and negligible with the SH3 domains of p21ras GTPase-activating protein and COOH-terminal Grb2. Distinct sites in the proline-rich COOH-terminal region of synapsin I were found to be involved in binding to the various SH3 domains. Synapsin II also interacted with SH3 domains with a partly distinct binding pattern. Phosphorylation of synapsin I in the COOH-terminal region by Ca2+/calmodulin-dependent protein kinase II or mitogen-activated protein kinase modulated the binding to the SH3 domains of amphiphysins I/II, Crk, and α-spectrin without affecting the high affinity interactions. The SH3-mediated interaction of synapsin I with amphiphysins affected the ability of synapsin I to interact with actin and synaptic vesicles, and pools of synapsin I and amphiphysin I were shown to associate in isolated nerve terminals. The ability to bind multiple SH3 domains further implicates the synapsins in signal transduction and protein-protein interactions at the nerve terminal level.
UR - http://www.scopus.com/inward/record.url?scp=0034703037&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034703037&partnerID=8YFLogxK
U2 - 10.1074/jbc.M006018200
DO - 10.1074/jbc.M006018200
M3 - Article
C2 - 10899172
AN - SCOPUS:0034703037
VL - 275
SP - 29857
EP - 29867
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 38
ER -