Heat-induced modulation of lamin B content in two different cell lines.
Previous work in our laboratory indicates that the nuclear matrix protein lamin B is a "prompt" heat shock protein, which increases significantly when human U-1 melanoma and HeLa cells are exposed to 45.5 degrees C for 5-40 min. Using Western blotting, we found that the lamin B content in U-1 and HeLa cells increased to a greater extent during post-heat incubation at 37 degrees C than during the heat dose itself. When HeLa cells were heated at 45.5 degrees C for 30 min, and then incubated at 37 degrees C for up to 7 h, lamin B content was increased significantly (1.69-fold maximum increase at 3 h) compared to unincubated heated cells. Also, thermotolerant HeLa cells showed a greater increase (up to 1.72-fold) in lamin B content during subsequent heating compared to nontolerant cells. The increase in lamin B content in thermotolerant cells, or when heated cells were incubated at 37 degrees C, was also observed in U-1 cells. HeLa cells heated in the presence of glycerol (a heat protector) showed a 1.21-1.72-fold increase in lamin B content compared to cells heated for 10-30 min without glycerol. In contrast, lamin B content decreased 1.23-1.85-fold when cells were heated for 10-30 min in the presence of procaine (a heat sensitizer) compared to cells heated without procaine. These data suggest that lamin B may play an important role in the heat shock response, and that modulation of lamin B content by heat sensitizers or protectors may play a role in regulation of heat sensitivity.
Zhu
W G
WG
Indiana University School of Medicine, Department of Radiation Oncology, Indiana Cancer Pavilion, Indianapolis, Indiana 46202, USA.
Roberts
Z V
ZV
Dynlacht
J R
JR
D000779:Anesthetics, Local / Q000494:pharmacology; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D005990:Glycerol / Q000494:pharmacology; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism*; D018869:Heat-Shock Response / Q000187:drug effects; D006801:Humans; D034921:Lamin Type B; D034882:Lamins; D008545:Melanoma / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D011343:Procaine / Q000494:pharmacology; D013997:Time Factors; D014407:Tumor Cells, Cultured
D000779:Anesthetics, Local; D034921:Lamin Type B; D034882:Lamins; D009687:Nuclear Proteins; D011343:Procaine; D005990:Glycerol