WASPs with memory

Memory may not be confined to brain cells. Eduardo Torres and Michael Rosen (University of Texas Southwestern Medical Center, Dallas, TX) have found that the actin polymerization activator WASP has at least the potential to be a memory device. Such a capacity could switch cells into an altered state in which they respond more acutely to a stimulus the second time around.

Rosen was intrigued initially by the location of a tyrosine in WASP that others had found was phosphorylated. In structural models, Tyr 291 is buried in the fold that forms in the autoinhibisted form of WASP. Sure enough, Tyr 291 could only be phosphorylated (thus further activating WASP activity) when the structure was opened up via addition of the activating Cdc42.

Both Tyr 291 phosphorylation and Cdc42 activation can be driven...