An IκB-β COOH terminal region protein is essential for the proliferation of CHO cells under acidic stress

✍ Scribed by Qizong Lao; Osamu Kuge; Toshihiko Fukamachi; Tomohito Kakegawa; Hiromi Saito; Masahiro Nishijima; Hiroshi Kobayashi

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 230 KB
• Volume: 203
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.20221

✦ Synopsis

Abstract

CHO‐K1 cells were able to proliferate and maintain pHi homeostasis at pH 6.3. A novel acidic sensitive mutant, AS‐5B, which proliferated at pH 7.4 but failed to either proliferate or maintain pHi homeostasis at pH 6.3, was derived from CHO‐K1 using a replica method. The acidic‐sensitivity of AS‐5B was not due to deficiencies in sodium proton exchangers, HCO (co)transporters or H^+^‐ATPases. A cDNA clone encoding a COOH terminal region of IκB‐β conferred partial acidic‐resistance on AS‐5B, and the encoded protein was present in CHO‐K1, but was nearly absent from AS‐5B. Our data demonstrated that the expression of this small protein was essential for the proliferation of CHO cells under acidic stress. © 2004 Wiley‐Liss, Inc.