Characterization of latent transforming growth factor-beta 2 from monkey kidney cells.
Serum-free medium conditioned by BSC-40 cells was analyzed for the presence of transforming growth factor-beta 2 (TGF beta 2)-related proteins. Western blot analysis was performed using site-specific antipeptide antibodies directed against the pro- and mature regions of the TGF beta 2 precursor. When conditioned medium was analyzed by polyacrylamide gel electrophoresis under reducing conditions, proteins with mol wt of 53 kDa (containing both mature and proregion sequences), 34-38 kDa (containing proregion sequences only), and 12 kDa (containing mature sequences) were detected. Under nonreducing conditions, complexes of 60- to 80-kDa, 160- to 200-kDa, as well as 24-kDa mature dimers were seen. Cleavage of mature TGF beta 2 from its precursor was inhibited by monensin and chloroquin, but not by ammonium chloride or methylamine. Two peaks of bioactivity were detected after fractionation on a TSK column corresponding to mol wt of 130 and 400 kDa. These peaks contained TGF beta 2 and pro-TGF beta 2 proteins. Partial purification of the 130-kDa complex followed by N-glyconase digestion indicated that the pro-TGF beta 2 proteins were glycosylated. These data demonstrate that BSC-40 cells secrete mature TGF beta 2 complexed with proregion-containing proteins and suggest that this association may contribute to the latency phenomena observed with respect to this growth regulator.
Lioubin
M N
MN
Oncogen, Seattle, Washington 98121.
Madisen
L
L
Roth
R A
RA
Purchio
A F
AF
D000581:Amidohydrolases; D000818:Animals; D002460:Cell Line; D002845:Chromatography; D000882:Haplorhini; D015151:Immunoblotting; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D011480:Protease Inhibitors / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D011480:Protease Inhibitors; D016212:Transforming Growth Factor beta; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase