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An IκB‐β COOH terminal region protein is essential for the proliferation of CHO cells under acidic stress
Author(s) -
Lao Qizong,
Kuge Osamu,
Fukamachi Toshihiko,
Kakegawa Tomohito,
Saito Hiromi,
Nishijima Masahiro,
Kobayashi Hiroshi
Publication year - 2005
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.20221
Subject(s) - terminal (telecommunication) , microbiology and biotechnology , chemistry , chinese hamster ovary cell , stress (linguistics) , cell growth , biochemistry , biology , computer science , telecommunications , receptor , linguistics , philosophy
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 3 −(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.