title: Secretion of a unique collagen by spontaneously transformed murine keratinocytes (PAM cells) in vitro.
abstract: A spontaneously transformed murine keratinocyte cell line (PAM cell) was found to secrete two nondisulfide-linked collagenous polypeptides with apparent molecular weight (MW) 190-kd and 120-kd. Pulse-chase experiments indicated that the 190-kd polypeptide was secreted into the culture medium in 2 h and processed to the 120-kd collagen component within 4 h. This process was inhibited by EDTA. The 120-kd polypeptide was sensitive to pepsin, and a 50-kd fragment was produced by a mild pepsin treatment at 4 degrees C. A cyanogen bromide peptide map of the 120-kd polypeptide was distinct from that of types I, II, III, IV, and V collagens. These properties indicate similarities to the type VIII-related collagen produced by human astrocytoma cells. The secretion of the collagen rapidly reached a maximum level on the first day of culture and subsequently declined with cell proliferation. An accelerated processing to the 120-kd polypeptide was observed under culture conditions of high cell density. Similar collagens were also found to be produced by normal human keratinocytes. These results indicate that the 120-kd polypeptide is a potentially functional protein that may participate in the formation of the extracellular matrix of keratinocytes.
authors.affiliation: Department of Dermatology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Tokimitsu
authors.forename: K
authors.initials: K
authors.lastname: Ohyama
authors.forename: S
authors.initials: S
authors.lastname: Tajima
authors.forename: T
authors.initials: T
authors.lastname: Nishikawa
mesh_terms: D000818:Animals; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D002848:Chromatography, DEAE-Cellulose; D003094:Collagen / Q000096:biosynthesis* / Q000302:isolation & purification; D003488:Cyanogen Bromide; D004591:Electrophoresis, Polyacrylamide Gel; D005944:Glucosamine / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism; D051379:Mice; D008970:Molecular Weight; D010449:Peptide Mapping; D011392:Proline / Q000378:metabolism; D014316:Tritium
chemical_list: D014316:Tritium; D003094:Collagen; D011392:Proline; D005944:Glucosamine; D003488:Cyanogen Bromide; D008358:Mannose