Effect of tunicamycin on glycosylation of a 50 kDa protein and thermotolerance development.
We investigated whether or not a 50 kDa glycoprotein might play an important role in protein synthesis-independent thermotolerance development in CHO cells. When cells were heated for 10 min at 45.5 degrees C, they became thermotolerant to a heat treatment at 45.5 degrees C administered 12 hr later. The thermotolerance ratio at 10(-3) isosurvival was 4.4. The cellular heat shock response leads to enhanced glycosylation of a 50 kDa protein. The glycosylation of proteins including a 50 kDa glycoprotein was inhibited by treatment with various concentrations of tunicamycin (0.2-2 micrograms/ml). The development of thermotolerance was not affected by treatment with tunicamycin after the initial heat treatment, although 2 micrograms/ml tunicamycin inhibited glycosylation by 95%. However, inhibiting protein synthesis with cycloheximide (10 micrograms/ml) after the initial heat treatment partially inhibited the development of thermotolerance. Nevertheless, there was no further reduction of thermotolerance development by treatment with a combination of 2 micrograms/ml tunicamycin and 10 micrograms/ml cycloheximide. These data suggest that development of thermotolerance, especially protein synthesis-independent thermotolerance, is not correlated with increased glycosylation of the 50 kDa protein.
Lee
Y J
YJ
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan 48073.
Kim
D
D
Hou
Z Z
ZZ
Corry
P M
PM
D000818:Animals; D016466:CHO Cells; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D003513:Cycloheximide / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism*; D006031:Glycosylation; D008970:Molecular Weight; D013696:Temperature; D014415:Tunicamycin / Q000494:pharmacology*
D006023:Glycoproteins; D014415:Tunicamycin; D003513:Cycloheximide