Bone morphogenetic protein and growth differentiation factor cytokine families and their protein antagonists

2010 ◽  
Vol 429 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Christopher C. Rider ◽  
Barbara Mulloy

The BMPs (bone morphogenetic proteins) and the GDFs (growth and differentiation factors) together form a single family of cystine-knot cytokines, sharing the characteristic fold of the TGFβ (transforming growth factor-β) superfamily. Besides the ability to induce bone formation, which gave the BMPs their name, the BMP/GDFs display morphogenetic activities in the development of a wide range of tissues. BMP/GDF homo- and hetero-dimers interact with combinations of type I and type II receptor dimers to produce multiple possible signalling complexes, leading to the activation of one of two competing sets of SMAD transcription factors. BMP/GDFs have highly specific and localized functions. These are regulated in a number of ways, including the developmental restriction of BMP/GDF expression and through the secretion of several specific BMP antagonist proteins that bind with high affinity to the cytokines. Curiously, a number of these antagonists are also members of the TGF-β superfamily. Finally a number of both the BMP/GDFs and their antagonists interact with the heparan sulphate side chains of cell-surface and extracellular-matrix proteoglycans.

2006 ◽  
Vol 34 (3) ◽  
pp. 458-460 ◽  
Author(s):  
C.C. Rider

The TGF-β (transforming growth factor-β) cytokine superfamily in mammals contains some 30 members. These dimeric proteins are characterized by a strongly conserved cystine knot-based structure. They regulate the proliferation, differentiation and migration of many cell types, and therefore have important roles in morphogenesis, organogenesis, tissue maintenance and wound healing. Thus far, around one-quarter of these cytokines have been shown to bind to heparin and heparan sulphate. Well-established examples are the TGF-β isoforms 1 and 2, and the BMPs (bone morphogenetic proteins) -2 and -4. In studies in my laboratory, we have shown that GDNF (glial-cell-line-derived neurotrophic factor) and its close relatives neurturin and artemin bind to heparin and heparan sulphate with high affinity. We have reported previously that binding of GDNF is highly dependent on the presence of 2-O-sulphate groups. More recently, we and others have been investigating the heparin/heparan sulphate-binding properties of BMP-7, which is a representative of a distinct BMP subgroup from that of BMPs -2 and -4. Interestingly, several of the various specific BMP antagonist proteins also bind to heparin and heparan sulphate. Much remains to be learnt about the nature and role of glycosaminoglycan interactions in the TGF-β superfamily, but current work suggests that these cytokines do not share a single highly conserved heparin/heparan sulphate-binding site.


2003 ◽  
Vol 14 (7) ◽  
pp. 2809-2817 ◽  
Author(s):  
Gyo Murakami ◽  
Tetsuro Watabe ◽  
Kunio Takaoka ◽  
Kohei Miyazono ◽  
Takeshi Imamura

Smad ubiquitin regulatory factor (Smurf) 1 binds to receptor-regulated Smads for bone morphogenetic proteins (BMPs) Smad1/5 and promotes their degradation. In addition, Smurf1 associates with transforming growth factor-β type I receptor through the inhibitory Smad (I-Smad) Smad7 and induces their degradation. Herein, we examined whether Smurf1 negatively regulates BMP signaling together with the I-Smads Smad6/7. Smurf1 and Smad6 cooperatively induced secondary axes in Xenopus embryos. Using a BMP-responsive promoter-reporter construct in mammalian cells, we found that Smurf1 cooperated with I-Smad in inhibiting BMP signaling and that the inhibitory activity of Smurf1 was not necessarily correlated with its ability to bind to Smad1/5 directly. Smurf1 bound to BMP type I receptors via I-Smads and induced ubiquitination and degradation of these receptors. Moreover, Smurf1 associated with Smad1/5 indirectly through I-Smads and induced their ubiquitination and degradation. Smurf1 thus controls BMP signaling with and without I-Smads through multiple mechanisms.


2000 ◽  
Vol 11 (3) ◽  
pp. 1023-1035 ◽  
Author(s):  
Lilach Gilboa ◽  
Anja Nohe ◽  
Tanja Geissendörfer ◽  
Walter Sebald ◽  
Yoav I. Henis ◽  
...  

The bone morphogenetic proteins (BMPs) play important roles in embryogenesis and normal cell growth. The BMP receptors belong to the family of serine/threonine kinase receptors, whose activation has been investigated intensively for the transforming growth factor-β (TGF-β) receptor subfamily. However, the interactions between the BMP receptors, the composition of the active receptor complex, and the role of the ligand in its formation have not yet been investigated and were usually assumed to follow the same pattern as the TGF-β receptors. Here we demonstrate that the oligomerization pattern of the BMP receptors is different and is more flexible and susceptible to modulation by ligand. Using several complementary approaches, we investigated the formation of homomeric and heteromeric complexes between the two known BMP type I receptors (BR-Ia and BR-Ib) and the BMP type II receptor (BR-II). Coimmunoprecipitation studies detected the formation of heteromeric and homomeric complexes among all the BMP receptor types even in the absence of ligand. These complexes were also detected at the cell surface after BMP-2 binding and cross-linking. Using antibody-mediated immunofluorescence copatching of epitope-tagged receptors, we provide evidence in live cells for preexisting heteromeric (BR-II/BR-Ia and BR-II/BR-Ib) and homomeric (BR-II/BR-II, BR-Ia/ BR-Ia, BR-Ib/ BR-Ib, and also BR-Ia/ BR-Ib) oligomers in the absence of ligand. BMP-2 binding significantly increased hetero- and homo-oligomerization (except for the BR-II homo-oligomer, which binds ligand poorly in the absence of BR-I). In contrast to previous observations on TGF-β receptors, which were found to be fully homodimeric in the absence of ligand, the BMP receptors show a much more flexible oligomerization pattern. This novel feature in the oligomerization mode of the BMP receptors allows higher variety and flexibility in their responses to various ligands as compared with the TGF-β receptors.


Open Biology ◽  
2012 ◽  
Vol 2 (4) ◽  
pp. 120060 ◽  
Author(s):  
Elizabeth M. Callery ◽  
Chong Yon Park ◽  
Xin Xu ◽  
Haitao Zhu ◽  
James C. Smith ◽  
...  

Transforming growth factor β superfamily members signal through Smad transcription factors. Bone morphogenetic proteins (BMPs) act via Smads 1, 5 and 8 and TGF-βs signal through Smads 2 and 3. The endocytic adaptor protein Eps15R, or ‘epidermal growth factor (EGF) receptor pathway substrate 15-related protein’ is a component of EGF signal transduction, mediating internalization of the EGF receptor. We show that it interacts with Smad proteins, is required for BMP signalling in animal caps and stimulates Smad1 transcriptional activity. This function resides in the Asp-Pro-Phe motif-enriched ‘DPF domain’ of Eps15R, which activates transcription and antagonizes Smad2 signalling. In living cells, Eps15R segregates into spatially distinct regions with different Smads, indicating an unrecognized level of Smad compartmentalization.


2001 ◽  
Vol 155 (6) ◽  
pp. 1017-1028 ◽  
Author(s):  
Aki Hanyu ◽  
Yasuhiro Ishidou ◽  
Takanori Ebisawa ◽  
Tomomasa Shimanuki ◽  
Takeshi Imamura ◽  
...  

Inhibitory Smads (I-Smads) repress signaling by cytokines of the transforming growth factor-β (TGF-β) superfamily. I-Smads have conserved carboxy-terminal Mad homology 2 (MH2) domains, whereas the amino acid sequences of their amino-terminal regions (N domains) are highly divergent from those of other Smads. Of the two different I-Smads in mammals, Smad7 inhibited signaling by both TGF-β and bone morphogenetic proteins (BMPs), whereas Smad6 was less effective in inhibiting TGF-β signaling. Analyses using deletion mutants and chimeras of Smad6 and Smad7 revealed that the MH2 domains were responsible for the inhibition of both TGF-β and BMP signaling by I-Smads, but the isolated MH2 domains of Smad6 and Smad7 were less potent than the full-length Smad7 in inhibiting TGF-β signaling. The N domains of I-Smads determined the subcellular localization of these molecules. Chimeras containing the N domain of Smad7 interacted with the TGF-β type I receptor (TβR-I) more efficiently, and were more potent in repressing TGF-β signaling, than those containing the N domain of Smad6. The isolated N domain of Smad7 physically interacted with the MH2 domain of Smad7, and enhanced the inhibitory activity of the latter through facilitating interaction with TGF-β receptors. The N domain of Smad7 thus plays an important role in the specific inhibition of TGF-β signaling.


2000 ◽  
Vol 11 (2) ◽  
pp. 555-565 ◽  
Author(s):  
Kiyoshi Kusanagi ◽  
Hirofumi Inoue ◽  
Yasuhiro Ishidou ◽  
Hiromu K. Mishima ◽  
Masahiro Kawabata ◽  
...  

Bone morphogenetic proteins (BMPs) are pleiotropic growth and differentiation factors belonging to the transforming growth factor-β (TGF-β) superfamily. Signals of the TGF-β-like ligands are propagated to the nucleus through specific interaction of transmembrane serine/threonine kinase receptors and Smad proteins. GCCGnCGC has been suggested as a consensus binding sequence for DrosophilaMad regulated by a BMP-like ligand, Decapentaplegic. Smad1 is one of the mammalian Smads activated by BMPs. Here we show that Smad1 binds to this motif upon BMP stimulation in the presence of the common Smad, Smad4. The binding affinity is likely to be relatively low, because Smad1 binds to three copies of the motif weakly, but more repeats of the motif significantly enhance the binding. Heterologous reporter genes (GCCG-Lux) with multiple repeats of the motif respond to BMP stimulation but not to TGF-β or activin. Mutational analyses reveal several bases critical for the responsiveness. A natural BMP-responsive reporter, pTlx-Lux, is activated by BMP receptors in P19 cells but not in mink lung cells. In contrast, GCCG-Lux responds to BMP stimulation in both cells, suggesting that it is a universal reporter that directly detects Smad phosphorylation by BMP receptors.


2017 ◽  
Vol 28 (12) ◽  
pp. 1612-1621 ◽  
Author(s):  
Aldo Leal-Egaña ◽  
Gaelle Letort ◽  
Jean-Louis Martiel ◽  
Andreas Christ ◽  
Timothée Vignaud ◽  
...  

Tumor development progresses through a complex path of biomechanical changes leading first to cell growth and contraction and then cell deadhesion, scattering, and invasion. Tumorigenic factors may act specifically on one of these steps or have a wider spectrum of actions, leading to a variety of effects and thus sometimes to apparent contradictory outcomes. Here we used micropatterned lines of collagen type I/fibronectin on deformable surfaces to standardize cell behavior and measure simultaneously cell size, speed of motion and magnitude of the associated traction forces at the level of a single cell. We analyzed and compared the normal human breast cell line MCF10A in control conditions and in response to various tumorigenic factors. In all conditions, a wide range of biomechanical properties was identified. Despite this heterogeneity, normal and transformed motile cells followed a common trend whereby size and contractile forces were negatively correlated with cell speed. Some tumorigenic factors, such as activation of ErbB2 or loss of the βsubunit of casein kinase 2, shifted the whole population toward a faster speed and lower contractility state. Treatment with transforming growth factor β induced some cells to adopt opposing behaviors such as extremely high versus extremely low contractility. Thus tumor transformation amplified preexisting population heterogeneity and led some cells to exhibit biomechanical properties that were more extreme than those observed with normal cells.


2002 ◽  
Vol 13 (11) ◽  
pp. 4001-4012 ◽  
Author(s):  
Diying Yao ◽  
Marcelo Ehrlich ◽  
Yoav I. Henis ◽  
Edward B. Leof

Transforming growth factor-β (TGF-β) superfamily members regulate a wide range of biological processes by binding to two transmembrane serine/threonine kinase receptors, type I and type II. We have previously shown that the internalization of these receptors is inhibited by K+ depletion, cytosol acidification, or hypertonic medium, suggesting the involvement of clathrin-coated pits. However, the involvement of the clathrin-associated adaptor complex AP2 and the identity of the AP2 subunit that binds the receptors were not known. Herein, we have studied these issues by combining studies on intact cells with in vitro assays. Using fluorescence photobleaching recovery to measure the lateral mobility of the receptors on live cells (untreated or treated to alter their coated pit structure), we demonstrated that their mobility is restricted by interactions with coated pits. These interactions were transient and mediated through the receptors' cytoplasmic tails. To measure direct binding of the receptors to specific AP2 subunits, we used yeast two-hybrid screens and in vitro biochemical assays. In contrast to most other plasma membrane receptors that bind to AP2 via the μ2 subunit, AP2/TGF-β receptor binding was mediated by a direct interaction between the β2-adaptin N-terminal trunk domain and the cytoplasmic tails of the receptors; no binding was observed to the μ2, α, or ς2 subunits of AP2 or to μ1 of AP1. The data uniquely demonstrate both in vivo and in vitro the ability of β2-adaptin to directly couple TGF-β receptors to AP2 and to clathrin-coated pits, providing the first in vivo evidence for interactions of a transmembrane receptor with β2-adaptin.


2004 ◽  
Vol 24 (10) ◽  
pp. 4241-4254 ◽  
Author(s):  
Marcin Kowanetz ◽  
Ulrich Valcourt ◽  
Rosita Bergström ◽  
Carl-Henrik Heldin ◽  
Aristidis Moustakas

ABSTRACT Transforming growth factors β (TGF-βs) inhibit growth of epithelial cells and induce differentiation changes, such as epithelial-mesenchymal transition (EMT). On the other hand, bone morphogenetic proteins (BMPs) weakly affect epithelial cell growth and do not induce EMT. Smad4 transmits signals from both TGF-β and BMP pathways. Stimulation of Smad4-deficient epithelial cells with TGF-β1 or BMP-7 in the absence or presence of exogenous Smad4, followed by cDNA microarray analysis, revealed 173 mostly Smad4-dependent, TGF-β-, or BMP-responsive genes. Among 25 genes coregulated by both factors, inhibitors of differentiation Id2 and Id3 showed long-term repression by TGF-β and sustained induction by BMP. The opposing regulation of Id genes is critical for proliferative and differentiation responses. Hence, ectopic Id2 or Id3 expression renders epithelial cells refractory to growth inhibition and EMT induced by TGF-β, phenocopying the BMP response. Knockdown of endogenous Id2 or Id3 sensitizes epithelial cells to BMP, leading to robust growth inhibition and induction of transdifferentiation. Thus, Id genes sense Smad signals and create a permissive or refractory nuclear environment that defines decisions of cell fate and proliferation.


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