Membrane proteins are challenging to study given their hydrophobic nature, generally low native abundance and intrinsic instability(1,2). Regardless, half of all protein drug targets are membrane proteins. For imaging, most fluorescent proteins (i.e. GFP) cannot specifically visualize cell surface subpopulations. However, CLIP-tag, SNAP-tag and cell surface-specific ACP/MCP-tag systems can specifically label subpopulations of target protein expressed on the cell surface using non-cell permeable substrates (3). This approach permits discrimination of different populations of a cell surface protein: those properly translocated to the plasma membrane from those retained in the secretory pathway or already internalized (e.g. upon ligand binding).
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- von Heijne G. (2007) J Intern Med. 261, 543–557. PMID: 17547710
- Keppler, A., Pick, H., Arrivoli, C. et al. (2004) Proc. Natl. Acad. Sci. USA, 101, 9955. PMID: 15226507
CLIP-tag™ is a trademark of New England Biolabs, Inc.
SNAP-tag® is a registered trademark of New England Biolabs, Inc.