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.
Lao
Qizong
Q
Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
Kuge
Osamu
O
Fukamachi
Toshihiko
T
Kakegawa
Tomohito
T
Saito
Hiromi
H
Nishijima
Masahiro
M
Kobayashi
Hiroshi
H
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