A rat pituitary tumor cell line (GH3) expresses type I and type II receptors and other cell surface binding protein(s) for transforming growth factor-beta.
A rat pituitary tumor cell line (GH3) has been reported to express transforming growth factor-beta (TGF-beta) binding components of 70-74 kDa (ligand included), denoted TGF-beta type IV receptor. We investigated whether the type IV receptor corresponds to any of the recently cloned type I receptors for proteins in the TGF-beta super-family. TGF-beta type I receptor (T beta R-I) complexes of 69-72 kDa formed a heteromeric complex with T beta R-II in GH3 cells, as detected by immunoprecipitation. In addition, TGF-beta formed complexes of 72-74 kDa, which were different from T beta R-I and the other known type I receptors, and were not dependent on T beta R-II for binding. The GH3 cells were resistant to the growth inhibitory activity of TGF-beta, but a transcriptional response was activated by TGF-beta in this cell line, presumably through the T beta R-II and T beta R-I complex. These results indicate that GH3 cells have T beta R-I and T beta R-II and, in addition, other binding protein(s) which form 72-74-kDa complexes with TGF-beta; the function of the latter component(s) remains to be elucidated.
Yamashita
H
H
Ludwig Institute for Cancer Research, Uppsala, Sweden.
Okadome
T
T
Franzén
P
P
ten Dijke
P
P
Heldin
C H
CH
Miyazono
K
K
D028341:Activins; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D007265:Inhibins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010911:Pituitary Neoplasms / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D008565:Membrane Proteins; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D028341:Activins; D007265:Inhibins