Referenced in: none

Automatically associated channels: Kv1.4

Title: Three fluorescent protein voltage sensors exhibit low plasma membrane expression in mammalian cells.

Authors: B J Baker, H Lee, V A Pieribone, L B Cohen, E Y Isacoff, T Knöpfel, E K Kosmidis

Journal, date & volume: J. Neurosci. Methods, 2007 Mar 30 , 161, 32-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/17126911

Abstract
Three first-generation fluorescent protein voltage sensitive probes (FP-voltage sensors) were characterized in mammalian cells. Flare, a Kv1.4 variant of FlaSh [Siegel MS, Isacoff EY. Neuron 1997;19(October (4)):735-41], SPARC [Ataka K, Pieribone VA. Biophys J 2002;82(January (1 Pt 1)):509-16], and VSFP-1 [Sakai R, Repunte-Canonigo V, Raj CD, Knopfel T. Eur J Neurosci 2001;13(June (12)):2314-18] were expressed, imaged and voltage clamped in HEK 293 cells and in dissociated hippocampal neurons. We were unable to detect a signal in response to changes in membrane potential after averaging16 trials with any of the three constructs. Using the hydrophobic voltage sensitive dye, di8-ANEPPS, as a surface marker, confocal analyses demonstrated poor plasma membrane expression for Flare, SPARC and VSFP-1 in both HEK 293 cells and dissociated hippocampal neurons. Almost all of the expressed FP-voltage sensors reside in internal membranes in both cell types. This internal expression generates a background fluorescence that increases the noise in the optical measurement.