The SH3p4/Sh3p8/SH3p13 protein family: binding partners for synaptojanin and dynamin via a Grb2-like Src homology 3 domain.
The GTPase dynamin I and the inositol 5-phosphatase synaptojanin are nerve terminal proteins implicated in synaptic vesicle recycling. Both proteins contain COOH-terminal proline-rich domains that can interact with a variety of Src homology 3 (SH3) domains. A major physiological binding partner for dynamin I and synaptojanin in the nervous system is amphiphysin I, an SH3 domain-containing protein also concentrated in nerve terminals. We have used the proline-rich tail of synaptojanin to screen a rat brain library by the two-hybrid method to identify additional interacting partners of synaptojanin. Three related proteins containing SH3 domains that are closely related to the SH3 domains of Grb2 were isolated: SH3p4, SH3p8, and SH3p13. Further biochemical studies demonstrated that the SH3p4/8/13 proteins bind to both synaptojanin and dynamin I. The SH3p4/8/13 transcripts are differentially expressed in tissues: SH3p4 mRNA was detected only in brain, SH3p13 mRNA was present in brain and testis, and the SH3p8 transcript was detected at similar levels in multiple tissues. Members of the SH3p4/8/13 protein family were found to be concentrated in nerve terminals, and pools of synaptojanin and dynamin I were coprecipitated from brain extracts with antibodies recognizing SH3p4/8/13. These findings underscore the important role of SH3-mediated interactions in synaptic vesicle recycling.
Ringstad
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Department of Cell Biology and Howard Hughes Medical Institute, Yale University School of Medicine, 295 Congress Avenue, New Haven, CT 06510, USA.
Nemoto
Y
Y
De Camilli
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P
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009928:Organ Specificity; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D012441:Saccharomyces cerevisiae; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins; D066246:ErbB Receptors; C097702:synaptojanin; D010744:Phosphoric Monoester Hydrolases