Synthesis and secretion of alpha 2-macroglobulin by human lung fibroblasts
Budek, W.; Danailov, M.L.; Bünning, P.; Afting, E.G.
Biochemical and Biophysical Research Communications 134(1): 57-63
1986
ISSN/ISBN: 0006-291X PMID: 2418827 Document Number: 272411
Synthesis and secretion of .alpha.2-macroglobulin were studied with the human lung fibroblast cell line GM 1379. After incubation with [3H]leucine the cells secreted radioactively labeled .alpha.2-macroglobulin consisting of subunits with a molecular weight of 180,000. When the cells were treated with tunicamycin the unglycosylated .alpha.2-macroglobulin subunit exhibited a molecular weight of 160,000. Poly(A)+RNA was isolated from the cultured cells and translated in a rabbit reticulocyte lysate. From the translation products an .alpha.2-macroglobulin species with a molecular weight of 160,000 was immunoprecipitated. The addition of pancreatic microsomes to the translation mixture resulted in the synthesis of an .alpha.2-macroglobulin subunit which had molecular weights of 180,000. Thus, a size of approximately 160,000 for the protein moiety and 20,000 for the carbohydrate portion can be estimated for a subunit of .alpha.2-macroglobulin from human lung fibroblasts.