Imaging CFTR protein localization in cultured cells and tissues

CFTR functions as a chloride channel at the apical membrane of airway, gastrointestinal, and other epithelial cells. Immunofluorescence microscopy is commonly used to assess the subcellular localization and relative abundance of CFTR. Visualization of heterologously overexpressed CFTR is typically unproblematic and straightforward, whereas detection of small quantities of endogenous CFTR in tissues can be challenging and requires highly specific antibodies and optimized staining protocols. CFTR tagged by green fluorescent protein can be employed to study trafficking in live cells. Tagging of CFTR with an extracellular epitope permits detection exclusively at the cell surface and subsequent chasing allows visualization of endocytic trafficking.