This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.104.056739v1 88/3/L20    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Han, X. Articles by Jackson, M. B. Search for Related Content PubMed PubMed Citation Articles by Han, X. Articles by Jackson, M. B.

Electrostatic Interactions between the Syntaxin Membrane Anchor and Neurotransmitter Passing through the Fusion Pore

Department of Physiology, University of Wisconsin, Madison, Wisconsin 53706

Correspondence: Address reprint requests and inquiries to Meyer Jackson, Email: mjackson{at}physiology.wisc.edu.

Recent experiments have shown that flux through the fusion pore is sensitive to manipulations of the side-chain size of certain residues in the syntaxin (syx) membrane anchor. These residues were proposed to line the wall of the fusion pore of Ca²⁺-triggered exocytosis. Here we continued this line of experimentation to examine possible electrostatic interactions between the pore lining residues and the neurotransmitter norepinephrine (NE). Replacing syx pore-lining residues with aspartate enhanced NE flux above that expected for the size of the aspartate side chain. In contrast, substitution with arginine reduced NE flux below that expected for the size of its side chain. Substituting aspartate and arginine into the nonpore-lining residues did not alter the fusion pore flux. Other amino acids with ionizable side chains had variable effects. These results indicate an electrostatic interaction between the pore-lining residues of syx and NE, and provide additional evidence that the syx membrane anchor is a structural component of the fusion pore.

This article has been cited by other articles:

				Z. Zhang and M. B. Jackson Temperature Dependence of Fusion Kinetics and Fusion Pores in Ca2+-triggered Exocytosis from PC12 Cells J. Gen. Physiol., January 28, 2008; 131(2): 117 - 124. [Abstract] [Full Text] [PDF]

				W. Liu, V. Montana, J. Bai, E. R. Chapman, U. Mohideen, and V. Parpura Single Molecule Mechanical Probing of the SNARE Protein Interactions Biophys. J., July 15, 2006; 91(2): 744 - 758. [Abstract] [Full Text] [PDF]