Identification and Characterization of a Nerve Terminal-enriched Amphiphysin Isoform*
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Québec H3A 2B4, Canada
Abstract
Amphiphysin is a nerve terminal-enriched protein thought to function in synaptic vesicle endocytosis, in part through Src homology 3 (SH3) domain-mediated interactions with dynamin and synaptojanin. Here, we report the characterization of a novel amphiphysin isoform (termed amphiphysin II) that was identified through a homology search of the data base of expressed sequence tags. Antibodies specific to amphiphysin II recognize a 90-kDa protein on Western blot that is brain-specific and highly enriched in nerve terminals. Like amphiphysin (now referred to as amphiphysin I), amphiphysin II binds to dynamin and synaptojanin through its SH3 domain. Further, both proteins bind directly to clathrin in an SH3 domain-independent manner. Taken together, these data suggest that amphiphysin II may participate with amphiphysin I in the regulation of synaptic vesicle endocytosis.
Footnotes
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↵* This work was supported in part by a Fonds de la Recherche en Santé du Québec Establishment Grant and by Medical Research Council of Canada Grant MT-12046 (to P. S. M.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) AF004015.
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↵‡ Recipient of a Jeanne Timmins Costello Studentship from the Montreal Neurological Institute.
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↵§ Medical Research Council of Canada Post-Doctoral Fellow.
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↵¶ Scholar of the Medical Research Council of Canada and an Alfred P. Sloan Research Fellow. To whom correspondence should be addressed. Tel.: 514-398-7355; Fax: 514-398-8106; E-mail:mcpm{at}musica.mcgill.ca.
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↵1 The abbreviations used are: SH3, Src homology 3; AP2, assembly protein 2; EST, expressed sequence tag; dbEST, EST data base; PCR, polymerase chain reaction; GST, glutathioneS-transferase; PBS, phosphate-buffered saline; PAGE, polyacrylamide gel electrophoresis.
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- Received January 29, 1997.
- Revision received April 9, 1997.
