Charged signaling

Areas of negative charge come and go on the plasma membrane, report Tony Yeung, Sergio Grinstein (Hospital for Sick Children, Toronto, Canada), and colleagues. Loss of the charged areas correlates with the loss of certain signaling proteins from the membrane and inactivation of related downstream activity.

Attraction based on charge is well established for sequence-specific protein–protein interactions. But the Toronto group documented an electrostatic switch that was evident with many different probes, with many different anionic lipids, and on liposomes that lacked any proteins. The probes were modeled on fragments of the K-Ras protein and combined polycationic sequences with a hydrophobic anchor to keep the probe in the plasma membrane rather than interacting with the anionic nucleoplasm.

The probes were displaced from the intracellular face of the plasma membrane by three different conditions: an...