Cell Biology. In the article “cAMP-mediated inhibition of the epithelial brush border NA⁺/H⁺ exchanger, NHE3, requires an associated regulatory protein” by C. H. Chris Yun, Soohyuk Oh, Mizra Zizak, Deborah Steplock, Su Tsao, Chung-Ming Tse, Edward J. Weinman, and Mark Donowitz, which appeared in number 7, April 1, 1997, of Proc. Natl. Acad. Sci. USA (94, 3010–3015), an error occurred in the nucleotide sequence of E3KARP at a position corresponding to amino acid 299 (Fig. 1A), which resulted in a frame-shift. A corrected nucleotide sequence has been deposited in the GenBank database (accession no. AF004900). E3KARP now encodes a protein of 337 amino acids with a deduced molecular weight of 37,400. NHERF is composed of 358 amino acids and not 353 amino acids as noted. A corrected portion of the figure (Fig. 1A) is reproduced below.