[Ser77]transforming growth factor-beta 1. Selective biological activity and receptor binding in mink lung epithelial cells.
Transforming growth factor-beta 1 (TGF-beta 1) is a homodimeric protein stabilized by a single disulfide bridge between Cys77 on the respective monomers and two paired complementary hydrophobic interfaces between the two subunits. A TGF-beta 1 mutant with Cys77 replaced by serine has been expressed in stably transfected Chinese hamster ovary cells and purified to homogeneity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirms that the sole interchain disulfide bond in TGF-beta 1 has been eliminated. It is 20% as potent as native TGF-beta 1 in the induction of plasminogen activator inhibitor-1 promoter expression in mink lung epithelial cells (Mv1Lu), although it is less than 1% as potent as native TGF-beta 1 in inhibition of growth in the same cell line. The mutant acts as a full agonist in both bioassays. [Ser77]TGF-beta 1 binds to soluble type II receptors and competes with native TGF-beta 1 in sandwich-enzyme-linked immunosorbent assays; however, in Mv1Lu cells, the mutant shows preferential cross-linking to type I rather than type II receptors. [Ser77]TGF-beta 1 is a useful tool for understanding the different ligand-receptor complexes and numerous biological activities of this multifunctional cytokine.
Amatayakul-Chantler
S
S
Laboratory of Chemoprevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892.
Qian
S W
SW
Gakenheimer
K
K
Böttinger
E P
EP
Roberts
A B
AB
Sporn
M B
MB
D000818:Animals; D001681:Biological Assay; D016466:CHO Cells; D002460:Cell Line; D006224:Cricetinae; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D066298:In Vitro Techniques; D051379:Mice; D008907:Mink; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism*; D011994:Recombinant Proteins; D012694:Serine / Q000737:chemistry; D013329:Structure-Activity Relationship; D016212:Transforming Growth Factor beta / Q000737:chemistry*
D004220:Disulfides; D018125:Receptors, Transforming Growth Factor beta; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D012694:Serine; D003545:Cysteine