Heat shock induces intestinal-type alkaline phosphatase in rat IEC-18 cells.
We demonstrate a previously unknown regulation for intestinal-type alkaline phosphatase (IAP) as a heat shock protein (HSP). Heat shock to rat intestinal epithelial cells (IEC)-18 at 43 degrees C induced the expression of IAP-I and HSP72 mRNAs time dependently (<60 min) but did not induce expression of IAP-II, tissue nonspecific-type alkaline phosphatase (TNAP), or HSP90 as determined by the RT-PCR method. To confirm the identity of the IAP-I gene, we sequenced the amplification product of IAP-I and found the gene to have 99% homology with the sequence of the IAP-I gene in rat intestine. Under the subculture conditions used, no IAP protein was detected in IEC-18 cells, but it became detectable as a 62-kDa band on a Western blot after heat shock. IAP-I was also induced by sodium arsenite, which generates reactive oxygen species and is an inducer of members of the HSP family. Glutathione suppressed activating protein-1 and cAMP response element-binding protein activation caused by heat shock but did not suppress the expression of IAP-I. These results suggest that cellular stress induces the elevation of IAP-I mRNA and protein synthesis. IAP-I may play an important role as a dephosphorylating enzyme under stress conditions.
Harada
Tsuyoshi
T
Department of Biochemistry, Saitama Medical School, Iruma-gun, Japan.
Koyama
Iwao
I
Kasahara
Toshihiko
T
Alpers
David H
DH
Komoda
Tsugikazu
T
D000469:Alkaline Phosphatase / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D018053:Arsenites / Q000494:pharmacology; D001483:Base Sequence; D015153:Blotting, Western; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006358:Hot Temperature; D007422:Intestines / Q000201:enzymology*; D007527:Isoenzymes / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics
D018053:Arsenites; D017362:Cyclic AMP Response Element-Binding Protein; D006360:Heat-Shock Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; D014157:Transcription Factors; D003609:Dactinomycin; D000469:Alkaline Phosphatase; D005978:Glutathione; C015001:arsenite