Physiology. In the article “Molecular cloning and expression of a cyclic AMP-activated chloride conductance regulator: A novel ATP-binding cassette transporter” by Marcel A. van Kuijck, Rémon A. M. H. van Aubel, Andreas E. Busch, Florian Lang, Frans G. M. Russel, René J. M. Bindels, Carel H. van Os, and Peter M. T. Deen, which appeared in number 11, May 28, 1996, of Proc. Natl. Acad. Sci. USA (93, 5401–5406), the authors wish to note the following. “The experiments involving expression in Xenopus oocytes cannot be reproduced. Therefore, the conclusion that this cDNA encodes a cAMP-regulated chloride transporter is incorrect. The correct functional activity of the cloned transporter has now been assessed by expression in insect Sf9 cells and reported in ref 1. The cloned cDNA turned out to be the rabbit homologue of the rat and human canalicular multispecific organic anion transporter, cMOAT, which is identical to the multidrug resistance-associated protein MRP2, as published in ref. 2. The sequence information is now available in GenBank (accession no. Z49144) under rabbit mrp2 gene for multidrug resistance-associated protein 2.”