The plasma membrane of a cell is riddled with many multi-protein complexes that facilitate communication and transport. These complexes provide a challenge to biologists due to their ubiquitous localization around the cell, their large, complex size, and their transient interactions with proteins. A recent paper describes a technique to study signaling complexes at the plasma membrane, using micropatterns within the plasma membrane. Löchte and colleagues expressed a protein bait in a micropattern in a living cell’s plasma membrane. Dynamics of the interactions between the protein bait and ligand target can then be quantified using live microscopy and on a single-molecule level. Löchte and colleagues used the IFN interferon signaling complex, using one of the receptor units (IFNAR2) as bait. In the top images above, the micropatterned receptor bait (IFNAR2) was able to recruit the other IFN receptor subunit (IFNAR1, green) after the addition of the ligand (red; time represents the addition of the ligand). Bottom image shows a closer view of the high-affinity, micropatterned binding that requires simultaneous interaction of the ligand (red) with both receptor subunits.
Lochte, S., Waichman, S., Beutel, O., You, C., & Piehler, J. (2014). Live cell micropatterning reveals the dynamics of signaling complexes at the plasma membrane originally published in the Journal of Cell Biology, 207 (3), 407-418 DOI: 10.1083/jcb.201406032