The role of syntaxins in the specificity of vesicle targeting in polarized epithelial cells

Martin B.A. Ter Beest, Steven J. Chapin, Dana Avrahami, Keith E. Mostov*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

In polarized epithelial cells syntaxin 3 is at the apical plasma membrane and is involved in delivery of proteins from the trans-Golgi network to the apical surface. The highly related syntaxin 4 is at the basolateral surface. The complementary distribution of these syntaxins suggests that they play a role in the specificity of membrane traffic to the two surfaces. We constructed a chimeric syntaxin where we removed the N-terminal 29 residues of syntaxin 3 and replaced it with the corresponding portion of syntaxin 4. When expressed in polarized epithelial cells, this chimera was exclusively localized to the basolateral surface. This indicates that the N-terminal domain of syntaxin 3 contains information for its polarized localization. In contrast to the apical localization of syntaxin 3, the basolateral localization of syntaxin 4 was not dependent on its N-terminal domain. Syntaxin 3 normally binds to Munc18b, but not to the related Munc18c. Overexpression of the chimera together with overexpression of Munc18b caused membrane and secretory proteins that are normally sent primarily to the apical surface to exhibit increased delivery to the basolateral surface. We suggest that syntaxins may play a role in determining the specificity of membrane targeting by permitting fusion with only certain target membranes.

Original languageAmerican English
Pages (from-to)5784-5792
Number of pages9
JournalMolecular Biology of the Cell
Volume16
Issue number12
DOIs
StatePublished - Dec 2005
Externally publishedYes

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