title: Accumulation of a high molecular weight glycoprotein during in vitro ageing and contact inhibition of growth.
abstract: A 240 000 molecular weight protein was found to accumulate in sorted autofluorescent (AF) cells, and during growth inhibition and in vitro ageing of cultures of human skin fibroblasts. Vitamin E, a lipophilic free radical scavenger which suppressed completely the formation of cellular autofluorescence, did not affect the accumulation of this protein. So, this accumulation is not related to cellular autofluorescence and lipid peroxidation, the major cause of this autofluorescence. This protein was also found in cells from a patient with the Spielmeyer-Vogt syndrome with a high percentage of maximal lifespan (MLS), while it was completely absent from all cells of a patient with Werner's syndrome. On two-dimensional gel electrophoresis the protein showed a heterogeneous acidic isoelectric point (IEP) of around 5.3. Neuraminidase treatment caused the IEP of this protein to shift towards a less acidic pH value (5.85). Upon differential centrifugation of a cell homogenate the protein was found to be located in the microsomal pellet and the cytosol. Chromatography on gelatin-sepharose revealed that the protein was not fibronectin. It is concluded that in human skin fibroblasts a high molecular weight glycoprotein accumulates as a result of impaired proliferation and that this accumulation is not related to cellular lipid peroxidation.
mesh_terms: D000328:Adult; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D002675:Child, Preschool; D003600:Cytosol / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005453:Fluorescence; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008861:Microsomes / Q000378:metabolism; D008970:Molecular Weight; D009472:Neuronal Ceroid-Lipofuscinoses / Q000378:metabolism; D013577:Syndrome; D013997:Time Factors; D014810:Vitamin E / Q000494:pharmacology; D014898:Werner Syndrome / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D014810:Vitamin E