Characterization of a type VI collagen-related Mr-140 000 protein from cutis-laxa fibroblasts in culture.
The precise biochemical defects in connective-tissue metabolism that are responsible for the laxity of skin seen in the syndrome of cutis laxa are largely unknown. We have studied fibroblasts cultured from skin explants of a 2-year-old male with the syndrome. Electron-microscopic examination of this skin revealed decreased amounts of amorphous elastin and an increase in elastin-associated microfibrils. Although the cultured fibroblasts were similar to control skin fibroblasts in morphology, growth rate and total protein synthesis, there was a 4-6-fold increase in accumulation of a collagenous protein of Mr 140 000 in both the culture medium and in the cell layer. This protein was structurally distinct from collagen types I, III, IV, V and VIII. It was found to be related to a cell-surface-associated glycoprotein, GP140, by both antigenic cross-reactivity and peptide mapping. Our data support observations that GP140 is a precursor of at least one form of pepsin-extracted type VI collagen.
D002478:Cells, Cultured; D002675:Child, Preschool; D002848:Chromatography, DEAE-Cellulose; D003094:Collagen / Q000276:immunology / Q000378:metabolism*; D003483:Cutis Laxa / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D010446:Peptide Fragments / Q000032:analysis; D014176:Protein Biosynthesis; D012867:Skin / Q000378:metabolism*
D010446:Peptide Fragments; D003094:Collagen