Patch-Clamp Fluorometry Recording of Conformational Rearrangements of Ion Channels

Conformational rearrangements are commonly observed in membrane proteins and constitute the molecular mechanisms through which they contribute to signal transduction. Information on structural changes in membrane proteins has mostly been inferred from functional studies. Recently, site-specific fluorescence recordings have made it possible to directly observe such molecular events in real time within the membrane environment. Here, we describe the patch-clamp fluorometry (PCF) technique that records simultaneously the local structural changes and the functional states of ion channels in isolated cell membranes. Combined with fluorescence resonance energy transfer (FRET), the technique should shed new light on ion channel activation, regulation, and interaction with other membrane proteins.