The Synaptobrevin-related Domains of Bos1p and Sec22p Bind to the Syntaxin-like Region of Sed5p*
- From the Howard Hughes Medical Institute and the Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510
Abstract
SNAREs (solubleN-ethylmaleimide-sensitive fusion proteinattachment protein receptors) are cytoplasmically oriented membrane proteins that reside on vesicular carriers (v-SNARE) and target organelles (t-SNARE). The pairing of a stage-specific v-SNARE with its cognate t-SNARE may mediate the specificity of membrane traffic. In the yeast Saccharomyces cerevisiae transport between the endoplasmic reticulum and Golgi complex employs two v-SNAREs, Bos1p and Sec22p, each containing a domain that is related to the neuronal v-SNARE synaptobrevin. Sed5p, which is homologous to syntaxin, is the t-SNARE that functions at this stage of the secretory pathway. Here we report that regions of Bos1p and Sec22p, which are homologous to synaptobrevin, bind to the syntaxin-like domain of Sed5p. Furthermore, we demonstrate that efficient v-SNARE/t-SNARE interactions require the participation of both v-SNAREs, indicating that, unlike post-Golgi membrane traffic, the active form of the endoplasmic reticulum to Golgi v-SNARE is a heteromeric complex.
Footnotes
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↵* 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.
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↵‡ Associate of the Howard Hughes Medical Institute.
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↵§ To whom correspondence should be addressed: Dept. of Cell Biology, Boyer Center for Molecular Medicine, Howard Hughes Medical Institute, 295 Congress Ave., Rm. 254B, New Haven, CT 06510. Tel.: 203-737-5207; Fax: 203-737-5746; E-mail:susan_ferronovick{at}quickmail.yale.edu.
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↵1 The abbreviations used are: ER, endoplasmic reticulum; SNARE, soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor; v, vesicular; t, target; GST, glutathione S-transferase.
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↵2 M. Sacher and S. Ferro-Novick, unpublished observations.
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↵3 S. Stone and S. Ferro-Novick, unpublished observations.
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- Received December 24, 1996.
- Revision received April 21, 1997.
