Erratum

Erratum:

The following correction should be noted for the Perspective by Mirshahi et al.:

In the figure legend on page 2 of the PDF, Asp323 should read Asp223.

The online full text view of the article has been corrected. A corrected PDF is available starting August 26, 2003.

A PDF of the originally published article with the original text is also available at http://stke.sciencemag.org/cgi/data/sigtrans;2003/194/pe32/DC1/1