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Updated: Jul 10, 2026

Determining Membrane Protein Topology Using Fluorescence Protease Protection (FPP)
Published on: April 20, 2015
Expression, localization, and topology of fluorescently tagged plasma membrane-targeted transmembrane proteins
Jeanne Shepshelovich1, Koret Hirschberg
1Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Abstract:
Transmembrane proteins constitute a significant proportion of the total number of proteins encoded in eukaryotic genomes. These proteins are involved in countless processes required for cellular function and homeostasis. Mutations mapping within their genes form the cellular mechanisms for a variety of pathological conditions. The surface expression of polytopic proteins can be limited by their relatively slow folding in the endoplasmic reticulum (ER). This is especially evident in heterologous overexpression systems . On the other hand, expression of these proteins in endogenously expressing primary cell lines is generally a challenging task in itself. Here we present a comprehensive scheme to establish arrival at the plasma membrane (PM) of transiently expressed, fluorescently tagged transmembrane proteins and provide two experimental tools to determine whether a distinct domain is cytosolic or extracellular using fluorescence microscopy.
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