An IkappaB-beta COOH terminal region protein is essential for the proliferation of CHO cells under acidic stress.
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, HCO3- (co)transporters or H+-ATPases. A cDNA clone encoding a COOH terminal region of IkappaB-beta 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.
Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
Qizong
Q
Lao
Osamu
O
Kuge
Toshihiko
T
Fukamachi
Tomohito
T
Kakegawa
Hiromi
H
Saito
Masahiro
M
Nishijima
Hiroshi
H
Kobayashi
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000143:Acids / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology; D000584:Amiloride / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001483:Base Sequence; D016466:CHO Cells; D019556:COS Cells; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002522:Chlorocebus aethiops; D002999:Clone Cells; D006224:Cricetinae; D003412:Cricetulus; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary; D005260:Female; D006706:Homeostasis / Q000187:drug effects / Q000502:physiology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D020672:I-kappa B Proteins / Q000737:chemistry / Q000235:genetics*; D018942:Macrolides / Q000494:pharmacology; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010053:Ovary / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D014162:Transfection
D000143:Acids; D000889:Anti-Arrhythmia Agents; D018076:DNA, Complementary; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D018942:Macrolides; D000584:Amiloride; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; C039614:ethylisopropylamiloride