A RAT PITUITARY-TUMOR CELL-LINE (GH(3)) EXPRESSES TYPE-I AND TYPE-II RECEPTORS AND OTHER CELL-SURFACE BINDING PROTEIN(S) FOR TRANSFORMING GROWTH-FACTOR-BETA
H. Yamashita et al., A RAT PITUITARY-TUMOR CELL-LINE (GH(3)) EXPRESSES TYPE-I AND TYPE-II RECEPTORS AND OTHER CELL-SURFACE BINDING PROTEIN(S) FOR TRANSFORMING GROWTH-FACTOR-BETA, The Journal of biological chemistry, 270(2), 1995, pp. 770-774
A rat pituitary tumor cell line (GH(3)) has been reported to express t
ransforming grow-th factor-beta (TGF-beta) binding components of 70-74
kDa (ligand included), denoted TGF-beta type IV receptor. We investig
ated whether the type IV receptor corresponds to any of the recently c
loned type I receptors for proteins in the TGF-beta superfamily. TGF-b
eta type I receptor (T beta R-I) complexes of 69-72 kDa formed a heter
omeric complex with T beta R-II in GH(3) cells, as detected by immunop
recipitation. In addition, TGF-beta formed complexes of 72-74 kDa, whi
ch 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 GH(3) cells w
ere resistant to the growth inhibitory activity of TGF-beta, but a tra
nscriptional response was activated by TGF-beta in this cell line, pre
sumably through the T beta R-II and T beta R-I complex. These results
indicate that GH(3) cells have T beta R-I and T beta R-II and, in addi
tion, other binding protein(s) which form 72-74-kDa complexes with TGF
-beta; the function of the latter component(s) remains to be elucidate
d.