scholarly journals The types II and III transforming growth factor-beta receptors form homo-oligomers.

1994 ◽  
Vol 126 (1) ◽  
pp. 139-154 ◽  
Author(s):  
Y I Henis ◽  
A Moustakas ◽  
H Y Lin ◽  
H F Lodish
Keyword(s):  
Growth Factor ◽  
Cell Surface ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Type Ii ◽  
Tgf Beta ◽  
Double Labeling ◽  
Beta Receptors ◽  
Growth Factor Beta ◽  
In Cells

Affinity-labeling experiments have detected hetero-oligomers of the types I, II, and III transforming growth factor beta (TGF-beta) receptors which mediate intracellular signaling by TGF-beta, but the oligomeric state of the individual receptor types remains unknown. Here we use two types of experiments to show that a major portion of the receptor types II and III forms homo-oligomers both in the absence and presence of TGF-beta. Both experiments used COS-7 cells co-transfected with combinations of these receptors carrying different epitope tags at their extracellular termini. In immunoprecipitation experiments, radiolabeled TGF-beta was bound and cross-linked to cells co-expressing two differently tagged type II receptors. Sequential immunoprecipitations using anti-epitope monoclonal antibodies showed that type II TGF-beta receptors form homo-oligomers. In cells co-expressing epitope-tagged types II and III receptors, a low level of co-precipitation of the ligand-labeled receptors was observed, indicating that some hetero-oligomers of the types II and III receptors exist in the presence of ligand. Antibody-mediated cross-linking studies based on double-labeling immunofluorescence explored co-patching of the receptors at the cell surface on live cells. In cells co-expressing two differently tagged type II receptors or two differently tagged type III receptors, forcing one receptor into micropatches by IgG induced co-patching of the receptor carrying the other tag, labeled by noncross-linking monovalent Fab'. These studies showed that homo-oligomers of the types II and III receptors exist on the cell surface in the absence or presence of TGF-beta 1 or -beta 2. In cells co-expressing types II and III receptors, the amount of heterocomplexes at the cell surface was too low to be detected in the immunofluorescence co-patching experiments, confirming that hetero-oligomers of the types II and III receptors are minor and probably transient species.

scholarly journals Captopril reverses high-glucose-induced growth effects on LLC-PK1 cells partly by decreasing transforming growth factor-beta receptor protein expressions.

1996 ◽  
Vol 7 (8) ◽  
pp. 1207-1215 ◽  
Author(s):  
J Y Guh ◽  
M L Yang ◽  
Y L Yang ◽  
C C Chang ◽  
L Y Chuang
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
High Glucose ◽  
Transforming Growth Factor ◽  
Receptor Protein ◽  
Tgf Beta ◽  
Beta Receptor ◽  
Protein Expressions ◽  
Beta Receptors ◽  
Growth Factor Beta

Transforming growth factor beta (TGF-beta) may be important in the pathogenesis of diabetic nephropathy, and captopril is effective in treating this disorder. However, the mechanisms of this therapeutic effect as related to TGF-beta and its receptors are not known. Thus, the effects of captopril on cellular growth, TGF-beta 1, and TGF-beta receptors were studied in LLC-PK1 cells cultured in normal (11 mM) or high glucose (27.5 mM). This study found that glucose dose-dependently inhibited cellular mitogenesis while inducing hypertrophy in these cells at 72 h of culture, concomitantly with enhanced TGF-beta 1 messenger RNA (mRNA) and TGF-beta receptor Types I and II protein expressions. Captopril dose-dependently (0.1 to 10 mM) increased cellular mitogenesis and inhibited hypertrophy in these cells. Moreover, captopril also decreased TGF-beta receptor Types I and II protein expressions dose-dependently. However, TGF-beta 1 mRNA was not affected by captopril. It was concluded that high glucose decreased cellular mitogenesis while increasing hypertrophy concomitantly with increased TGF-beta 1 mRNA and TGF-beta receptors in LLC-PK1 cells. Captopril can reverse high-glucose-induced growth effects by decreasing TGF-beta receptor protein expressions.

Expression of transforming growth factor-beta type II receptor in rat lung is regulated during development

1995 ◽  
Vol 269 (3) ◽  
pp. L419-L426 ◽  
Author(s):  
Y. Zhao ◽  
S. L. Young
Keyword(s):  
Growth Factor ◽  
Blood Vessels ◽  
Lung Tissue ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Fetal Lung ◽  
Type Ii ◽  
Rat Lung ◽  
Tgf Beta ◽  
Growth Factor Beta

Transforming growth factor-beta (TGF-beta) is an autocrine/paracrine growth factor that regulates cell proliferation, differentiation, extracellular matrix production and various other cell functions in the lung. TGF-beta exerts its effects on cells by binding to transmembrane heteromeric serine-threonine kinase receptors. The expression and localization of specific TGF-beta receptors in the lung, however, have not yet been investigated. In the present studies, we isolated a 1,762-base pair cDNA containing the full-length coding sequence for TGF-beta type II receptor (T beta RII) from rat fetal lung with the use of polymerase chain reaction methods. The expression of T beta RII during lung development was examined by Northern analysis. A 5.1-kilobase T beta RII mRNA was detected in rat lung tissue. T beta RII mRNA was expressed in rat fetal lung tissue early in development, increased as development proceeded, reached maximal concentration postnatally, and then decreased to the adult level. The localization of T beta RII in fetal and postnatal rat lung tissue was investigated with the use of in situ hybridization performed with an antisense RNA probe. T beta RII gene was expressed in the mesenchymal tissue and in the epithelial lining of the developing airway at day 16 of gestation. The hybridization signal of T beta RII mRNA was also observed in the adventitial layer of small blood vessels. Expression of T beta RII gene in the developing airway epithelium occurred along a proximal-distal gradient. In postnatal lung, T beta RII mRNA was detected mainly in parenchymal tissues and blood vessels. Expression of T beta RII remained high in the interstitium of interalveolar septa.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Signaling activity of transforming growth factor beta type II receptors lacking specific domains in the cytoplasmic region.

1993 ◽  
Vol 13 (12) ◽  
pp. 7239-7247 ◽  
Author(s):  
R Wieser ◽  
L Attisano ◽  
J L Wrana ◽  
J Massagué
Keyword(s):  
Growth Factor ◽  
Tyrosine Kinase ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Tyrosine Kinase Receptors ◽  
Receptor Complex ◽  
Type Ii ◽  
Tgf Beta ◽  
Growth Factor Beta ◽  
Signaling Activity

The transforming growth factor beta (TGF-beta) type II receptor (T beta R-II) is a transmembrane serine/threonine kinase that contains two inserts in the kinase region and a serine/threonine-rich C-terminal extension. T beta R-II is required for TGF-beta binding to the type I receptor, with which it forms a heteromeric receptor complex, and its kinase activity is required for signaling by this complex. We investigated the role of various cytoplasmic regions in T beta R-II by altering or deleting these regions and determining the signaling activity of the resulting products in cell lines made resistant to TGF-beta by inactivation of the endogenous T beta R-II. TGF-beta binding to receptor I and responsiveness to TGF-beta in these cells can be restored by transfection of wild-type T beta R-II. Using this system, we show that the kinase insert 1 and the C-terminal tail of T beta R-II, in contrast to the corresponding regions in most tyrosine kinase receptors, are not essential to specify ligand-induced responses. Insert 2 is necessary to support the catalytic activity of the receptor kinase, and its deletion yields a receptor that is unable to mediate any of the responses tested. However, substitution of this insert with insert 2 from the activin receptor, ActR-IIB, does not diminish the ability of T beta R-II to elicit these responses. A truncated T beta R-II lacking the cytoplasmic domain still binds TGF-beta, supports ligand binding to receptor I, and forms a complex with this receptor. However, TGF-beta binding to receptor I facilitated by this truncated T beta R-II fails to inhibit cell proliferation, activate extracellular matrix protein production, or activate transcription from a promoter containing TGF-beta-responsive elements. We conclude that the transcriptional and antiproliferative responses to TGF-beta require both components of a heteromeric receptor complex that differs from tyrosine kinase receptors in its mode of signaling.

The transforming growth factor beta type II receptor can replace the activin type II receptor in inducing mesoderm

1994 ◽  
Vol 14 (6) ◽  
pp. 4280-4285
Author(s):  
A Bhushan ◽  
H Y Lin ◽  
H F Lodish ◽  
C R Kintner
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Full Range ◽  
Type Ii ◽  
Tgf Beta ◽  
Mesodermal Cell ◽  
Xenopus Embryos ◽  
Growth Factor Beta

The type II receptors for the polypeptide growth factors transforming growth factor beta (TGF-beta) and activin belong to a new family of predicted serine/threonine protein kinases. In Xenopus embryos, the biological effects of activin and TGF-beta 1 are strikingly different; activin induces a full range of mesodermal cell types in the animal cap assay, while TGF-beta 1 has no effects, presumably because of the lack of functional TGF-beta receptors. In order to assess the biological activities of exogenously added TGF-beta 1, RNA encoding the TGF-beta type II receptor was introduced into Xenopus embryos. In animal caps from these embryos, TGF-beta 1 and activin show similar potencies for induction of mesoderm-specific mRNAs, and both elicit the same types of mesodermal tissues. In addition, the response of animal caps to TGF-beta 1, as well as to activin, is blocked by a dominant inhibitory ras mutant, p21(Asn-17)Ha-ras. These results indicate that the activin and TGF-beta type II receptors can couple to similar signalling pathways and that the biological specificities of these growth factors lie in their different ligand-binding domains and in different competences of the responding cells.

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