Single‐ and Multiple‐Molecule Dynamics of the Signaling from H‐Ras to cRaf‐1 Visualized on the Plasma Membrane of Living Cells

It's alive! The authors investigated the molecular behavior of the enzyme GFP-Raf1 in response to epidermal growth factor in living HeLa cells, using multiple- and single-molecule fluorescence microscopy. The interaction between YFP-Ras and GFP-Raf1 was detected using fluorescent resonance energy transfer imaging (see picture). Single-molecule observations point to a locally heterogeneous signaling process between Ras and Raf1.