A VAMP7/Vti1a SNARE complex distinguishes a non-conventional traffic route to the cell surface used by KChIP1 and Kv4 potassium channels

Flowerdew, Sarah E and Burgoyne, Robert D ORCID: 0000-0002-9219-0387 (2009) A VAMP7/Vti1a SNARE complex distinguishes a non-conventional traffic route to the cell surface used by KChIP1 and Kv4 potassium channels. BIOCHEMICAL JOURNAL, 418 (3). pp. 529-540.

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Abstract

The KChIPs (K(+) channel-interacting proteins) are EF hand-containing proteins required for the traffic of channel-forming Kv4 K(+) subunits to the plasma membrane. KChIP1 is targeted, through N-terminal myristoylation, to intracellular vesicles that appear to be trafficking intermediates from the ER (endoplasmic reticulum) to the Golgi but differ from those underlying conventional ER-Golgi traffic. To define KChIP1 vesicles and the traffic pathway followed by Kv4/KChIP1 traffic, we examined their relationship to potential SNARE (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor) proteins mediating the trafficking step. To distinguish Kv4/KChIP1 from conventional constitutive traffic, we compared it to the traffic of the VSVG (vesicular-stomatitis virus G-protein). Expression of KChIP with single or triple EF hand mutations quantitatively inhibited Kv4/KChIP1 traffic to the cell surface but had no effect on VSVG traffic. KChIP1-expressing vesicles co-localized with the SNARE proteins Vti1a and VAMP7 (vesicle-associated membrane protein 7), but not with the components of two other ER-Golgi SNARE complexes. siRNA (small interfering RNA)-mediated knockdown of Vti1a or VAMP7 inhibited Kv4/KChIP1traffic to the plasma membrane in HeLa and Neuro2A cells. Vti1a and VAMP7 siRNA had no effect on VSVG traffic or that of Kv4.2 when stimulated by KChIP2, a KChIP with different intrinsic membrane targeting compared with KChIP1. The present results suggest that a SNARE complex containing VAMP7 and Vti1a defines a novel traffic pathway to the cell surface in both neuronal and non-neuronal cells.

Item Type:	Article
Additional Information:	Journal article The Biochemical journal Biochem J. 2009 Jan 13. ## TULIP Type: Articles/Papers (Journal) ##
Uncontrolled Keywords:	calcium-binding protein, K+ channel-interacting protein (KChIP), potassium channel, neuronal calcium sensor (NCS) protein, soluble N-ethylmaleimide-sensitive fusion proteinattachment protein receptor (SNARE)
Depositing User:	Symplectic Admin
Date Deposited:	05 Nov 2014 15:29
Last Modified:	16 Dec 2022 04:09
DOI:	10.1042/BJ20081736
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/2001479

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• A VAMP7/Vti1a SNARE complex distinguishes a non-conventional traffic route to the cell surface used by KChIP1 and Kv4 potassium channels. (deposited 05 Nov 2014 15:29) [Currently Displayed]