Unexpected expression of Hsp47, a replacement of one amino acid (Val 7 Leu) in the amino terminal region, in cultured human tumorigenic cell lines.
BACKGROUND
In general, it has been stated that keratin (K) molecules are glycosylated. During biochemical studies of K subunits, we encountered a glycoprotein that does not judge K subunits.


OBJECTIVE
This study was intended to elucidate how the above glycoprotein co-exists in the K fraction prepared from ISO-HAS (cultured angiosarcoma cell line).


METHODS
We analyzed and sequenced a remarkable spot, which was shown as a glycoprotein by periodic acid Sciff's (PAS) staining, in the K fraction prepared from ISO-HAS.


RESULTS
The glycoprotein was identified as an N-terminal amino acid sequence covering 10 residues of the spot. A homology search showed that it was identical to that of Hsp47 (matured type), except for one amino acid (seventh amino acid: Val 7 Leu). Similar results were confirmed for four other tumorigenic cell line types. Subsequent PAS staining using the same samples after 2D-PAGE revealed no glycosylated Ks.


CONCLUSIONS
No glycosylated Ks were found by PAS staining in the K fraction prepared from four tumorigenic cell line types. During K preparation from cultured human tumor cell lines, Hsps might be associated with K expression in tumor cells.
Katagata
Yohtaro
Y
Department of Biochemistry and Biotechnology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Aomori 037-8561, Japan. katagata@cc.hirosaki-u.ac.jp
Hirayama
Toshiya
T
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000502:physiology; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology*; D002461:Cell Line, Transformed; D005354:Fibrosarcoma; D015972:Gene Expression Regulation, Neoplastic; D006031:Glycosylation; D050958:HSP47 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism*; D006367:HeLa Cells; D006394:Hemangiosarcoma; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology*; D007633:Keratins / Q000378:metabolism; D008545:Melanoma; D008969:Molecular Sequence Data; D010503:Periodic Acid-Schiff Reaction; D012878:Skin Neoplasms / Q000503:physiopathology*
D050958:HSP47 Heat-Shock Proteins; C494660:SERPINH1 protein, human; D007633:Keratins