title: Corrections and clarifications.
abstract: In the report "Reversal of Raf-1 activation by purified and membrane-associated protein phosphatases" by P. Dent, T. Jelinek, D. K. Morrison, M. J. Weber, and T. W. Sturgill, (30 June, p. 1902), reference 25 on page 1906 should have included, after the first sentence, "Buffers (4) and buffer E contained 0.2% (v/v) 2-mercaptoethanol."