Immunology. In the article “Ubiquitin-dependent degradation of IκBα is mediated by a ubiquitin ligase Skp1/Cul1/F-box protein FWD1” by Shigetsugu Hatakeyama, Masatoshi Kitagawa, Keiko Nakayama, Michiko Shirane, Masaki Matsumoto, Kimihiko Hattori, Hideaki Higashi, Hiroyasu Nakano, Ko Okumura, Kazunori Onoé, Robert A. Good, and Kei-ichi Nakayama, which appeared in number 7, March 30, 1999, of Proc. Natl. Acad. Sci. USA (96, 3859–3863), due to printer’s error, the following changes should be noted. On page 3859 in the abstract, text, and footnote, the word “Cull 1” should be “Cul1.”