Heat shock protein hsp70 protects cells from thermal stress even after deletion of its ATP-binding domain.
Retroviral-mediated gene transfer experiments show that rodent cells become heat resistant when stably and constitutively expressing a cloned human gene encoding an intact human 70-kDa heat shock protein (hsp70). Cells expressing higher levels of the hsp70 protein generally tolerate thermal stress better, whereas cells expressing either of two mutated hsp70-encoding genes, one with a 4-base pair out-of-frame deletion and one with an in-frame deletion of codons 438-618, are heat sensitive. These results provide strong evidence that expression of hsp70 leads directly to thermal tolerance. Surprisingly, cells expressing a mutant hsp70 of a human gene missing codons 120-428 are, nevertheless, heat resistant. Because the deleted region of this mutant contains the ATP-binding domain of human hsp70, this domain appears dispensable in the hsp70-mediated protection of cells from thermal stress.
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Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
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Liu
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Rehman
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Lee
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D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002872:Chromosome Deletion; D003001:Cloning, Molecular; D015870:Gene Expression; D005822:Genetic Vectors; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D012190:Retroviridae / Q000235:genetics; D014162:Transfection
D006360:Heat-Shock Proteins; D009838:Oligodeoxyribonucleotides; D011993:Recombinant Fusion Proteins; D000255:Adenosine Triphosphate