Mapping of the ligand binding domain of the transforming growth factor beta receptor type III by deletion mutagenesis.

Pépin, Marie-Claude; Beauchemin, M.; Plamondon, J.; O’Connor-McCourt, Maureen D.

doi:10.1073/pnas.91.15.6997

Cited by 38 publications

(52 citation statements)

References 36 publications

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“…These studies identify two binding regions that are approximately located at the membrane-distal (amino-terminal) half (14,27) and at the membrane-proximal (carboxyl-terminal) half of betaglycan ectodomain (25,26). Because these halves contain the regions of similarity to endoglin and uromodulin, here we will refer to them as the E-related and the U-related regions, respectively (Fig.…”

Section: Betaglycan Deletion Mutagenesis Has Identified 2 Independentmentioning

confidence: 99%

“…1A). Several groups have utilized deletion mutants of the wild type receptor to map the ligand binding domain of betaglycan (14,(25)(26)(27)(28)(29). These studies show the existence of two ligand binding regions in betaglycan that roughly match to each half of its ectodomain, the membrane-distal and the membrane-proximal regions (26).…”

Section: Transforming Growth Factor-␤ (Tgf-␤)mentioning

confidence: 99%

“…For that purpose we constructed betaglycan mutants analogous to those described by Pepin et al (25), i.e. lacking the amino-terminal half of betaglycan ectodomain.…”

Section: Betaglycan Deletion Mutagenesis Has Identified 2 Independentmentioning

confidence: 99%

“…Regions-At least 20 deletion mutants of rat betaglycan have been created and assayed in eukaryotic expression systems with the purpose of mapping its TGF-␤ binding sites (14,(25)(26)(27). These studies identify two binding regions that are approximately located at the membrane-distal (amino-terminal) half (14,27) and at the membrane-proximal (carboxyl-terminal) half of betaglycan ectodomain (25,26).…”

Section: Betaglycan Deletion Mutagenesis Has Identified 2 Independentmentioning

confidence: 99%

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Ligand Binding and Functional Properties of Betaglycan, a Co-receptor of the Transforming Growth Factor-β Superfamily

Esparza-López

Montiel

Vilchis-Landeros

et al. 2001

Journal of Biological Chemistry

147

136

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In the present work we have functionally characterized these ligand binding regions. Similar to the wild type receptor, both regions bind TGF-␤2 with higher affinity than TGF-␤1. However, only the endoglin-related region increases the TGF-␤2 labeling of the TGF-␤ type II receptor, the so-called "TGF-␤ -presentation" function of the wild type receptor. Despite this preference, both regions as well as the wild type receptor mediate the TGF-␤2-dependent Smad2 phosphorylation, indicating that they can function indistinguishably as TGF-␤-enhancing coreceptors. On the other hand, we found that the recently described ability of the wild type betaglycan to bind inhibin A is a property of the core protein that resides in the uromodulin-related region. Binding competition experiments indicate that this region binds inhibin and TGF-␤ with the following relative affinities: TGF-␤2 > inhibin A > TGF-␤1. All together, the present results suggest that betaglycan ectodomain is endowed with two bona fide independent ligand binding domains that can perform specialized functions as co-receptors of distinct members of the TGF-␤ superfamily. Transforming growth factor-␤ (TGF-␤)1 is the prototype of a superfamily of growth factors involved in the regulation of cell proliferation, differentiation, and development (1, 2). TGF-␤ signals through a complex of transmembrane serine/threonine kinase receptors, the TGF-␤ type I and type II receptors. Ligand binding promotes the association between the type I and II receptors. In this complex, phosphorylation of the type I receptor kinase by the constitutively active type II receptor kinase results in its activation. Active type I receptor phosphorylates members of a novel family of transcriptional regulators, the Smads, which transduce the TGF-␤ signal into the cell nucleus (3, 4).TGF-␤ has two known co-receptors, betaglycan and endoglin, which are transmembrane glycoproteins with large extracellular regions that bind TGF-␤ and small cytoplasmatic regions without any clearly identifiable signaling motif (5-8). Betaglycan is a membrane proteoglycan containing heparan and chondroitin sulfate chains whose core protein binds all three TGF-␤ isoforms (9 -11). Betaglycan is capable of fine tuning the availability of TGF-␤ to the signaling receptors, thereby determining the outcome of the TGF-␤ stimulation (12, 13). This regulation is both positive and negative. Although the membrane-bound form of betaglycan increases the binding of TGF-␤ to the signaling complex, the soluble form of betaglycan prevents this binding and therefore blocks the actions of TGF-␤ (14). These effects are more dramatic for TGF-␤2, the isoform for which betaglycan has higher affinity (15-17). Expression of membrane betaglycan in cells that normally do not express this co-receptor increases their binding to TGF-␤2 and corrects for their low sensitivity to this TGF-␤ isoform (18,19). Presumably, this effect is mediated by a TGF-␤-induced "presentation complex" formed between membrane-bound betaglycan and the TGF-␤ type II rece...

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Section: Betaglycan Deletion Mutagenesis Has Identified 2 Independentmentioning

confidence: 99%

Section: Transforming Growth Factor-␤ (Tgf-␤)mentioning

confidence: 99%

“…For that purpose we constructed betaglycan mutants analogous to those described by Pepin et al (25), i.e. lacking the amino-terminal half of betaglycan ectodomain.…”

Section: Betaglycan Deletion Mutagenesis Has Identified 2 Independentmentioning

confidence: 99%

Section: Betaglycan Deletion Mutagenesis Has Identified 2 Independentmentioning

confidence: 99%

See 2 more Smart Citations

Ligand Binding and Functional Properties of Betaglycan, a Co-receptor of the Transforming Growth Factor-β Superfamily

Esparza-López

Montiel

Vilchis-Landeros

et al. 2001

Journal of Biological Chemistry

147

136

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“…The localization of the spermligand active high-mannose-type chain in bovine ZPB and ZPC should be clarified. Besides the zona proteins, the ZP domain has been found in several proteins: TGF-b type III receptor (betaglycan) from fetal and adult tissues [28,29], uromodulin (urinary Tamm-Horsfall glycoprotein of pregnant woman) [30], the major zymogen granule membrane protein (GP-2) [31], and the proteins in the uterus and oviduct [32,33]. Furthermore, tectorins in the tectorial membranes responsible for hearing also have a ZP domain [34,35].…”

Section: Discussionmentioning

confidence: 99%

Localization of N‐linked carbohydrate chains in glycoprotein ZPA of the bovine egg zona pellucida

Ikeda

Yonezawa

Naoi

et al. 2002

European Journal of Biochemistry

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The zona pellucida, a transparent envelope surrounding the mammalian oocyte, consists of three glycoproteins, ZPA, ZPB and ZPC, and plays a role in sperm-egg interactions. In bovines, these glycoproteins cannot be separated unless the acidic N-acetyllactosamine regions of the carbohydrate chains are removed by endo-b-Galactosidase digestion. Endo-b-Galactosidase-digested ZPB retains stronger spermbinding activity than ZPC. It is still unclear whether ZPA possesses significant activity. Recently, we reported that bovine sperm binds to Man 5 GlcNAc 2 , the neutral N-linked chain in the cow zona proteins. In this study, we investigated the localization of the sperm-ligand active high-mannosetype chain and the acidic complex-type chains in bovine ZPA. Three N-glycopeptides of ZPA, containing an N-glycosylation site at Asn83, Asn191 and Asn527, respectively, were obtained from endo-b-Galactosidase-digested ZPA. Of these glycosylation sites, only Asn527 is present in the ZP domain common to all the zona proteins. The carbohydrate structures of the N-linked chains obtained from each N-glycopeptide were characterized by two-dimensional sugar mapping analysis, while considering the structures of the N-linked chains of the zona protein mixture reported previously. Acidic complex-type chains were found at all three N-glycosylation sites, while Man 5 GlcNAc 2 was found at Asn83 and Asn191, but there was very little of this spermligand active chain at Asn527 in the ZP domain of ZPA.Keywords: glycoprotein; N-linked carbohydrate chain; sperm ligand; zona pellucida; ZP domain.The mammalian oocyte is coated with a transparent matrix called the zona pellucida. This matrix plays various roles in the early phase of fertilization: species-specific sperm binding, blocking polyspermy, and protecting the embryo until implantation [1,2]. The zona is composed of three glycoproteins, called ZPA, ZPB and ZPC in the order of the size of their cDNAs [3], and their carbohydrate chains are responsible for species-specific sperm-zona binding [1,4].In the pig, the carbohydrate structures of O-linked chains of zona protein mixture [5,6] and the acidic and neutral N-linked chains of ZPB/ZPC mixture [7,8] are well characterized. Sperm-binding activity has been ascribed to the O-linked chains of the zona protein mixture [9] or to the neutral N-linked chains obtained from the ZPB/ZPC mixture [8]. We have shown that the triantennary/tetraantennary chains of the ZPB/ZPC mixture possess greater activity than the diantennary chains [10]. The triantennary/ tetraantennary chains of ZPB are localized at Asn220 in the N-terminal region [10]. Moreover, the isolated N-terminal peptide of ZPB including Asn220 has sperm-binding activity [11]. Yurewicz et al. [12] showed that ZPB and ZPC form heterocomplexes that have sperm-binding activity, but that monomeric ZPB or ZPC does not exhibit this activity. These results suggest that ZPC contributes to the expression of the sperm-binding activity of the neutral N-linked chain of ZPB. In ZPC, the triantennary/tetraante...

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Transforming growth factor‐β receptor expression on endothelial cells: Heterogeneity of type III receptor expression

Morello

Plamondon

Meyrick

et al. 1995

Journal Cellular Physiology

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Recent studies of whole animal responses have defined a role for circulating TGF-beta in the preservation and stabilization of microvascular endothelial function (Lefer et al. [1993] Proc. Natl. Acad. Sci. U.S.A., 90:1018-1022; Pfister et al. [1992] J. Exp. Med., 176:265-269). In order to determine which TGF-beta receptor types are responsible for this endothelial cell responsiveness, we used an affinity-labeling technique with 125I-TGF-beta 1 and -beta 2 to characterize TGF-beta receptors on five different endothelial cell cultures: early passage bovine lung and rat epididymal fat pad microvascular endothelial cells (BLMEC and REEC), established endothelial cell lines from bovine adrenal medulla capillaries (EJG), fetal bovine heart (FBHE), and bovine pulmonary artery (CPAE). Since it is known that endothelial cells from different parts of the vasculature vary with respect to cell surface antigen expression (McCarthy et al. [1991] Trends Pharmacol. Sci., 12:462-467; Augustin et al. [1994] Bioessays, 16:901-906), it is important to compare TGF-beta receptor expression on microvascular and macrovascular endothelial cells. We observed 85 kDa and 200-400 kDa labeled receptor bands and analyzed their relationship to the cloned Type II and III receptors using peptide antibodies. We used dithiothreitol and phosphoinositol-phospholipase C pretreatments to establish whether the 65 kDa labeled band which we observed corresponded to the Type I receptor or a glycophosphotidylinositol-linked binding protein. The results demonstrated that microvascular but not macrovascular endothelial cells express high levels of the Type III receptor. This differential expression of the Type III receptor indicates that distinct anatomical segments of the vasculature have distinct TGF-beta receptor profiles. The presence of the Type III receptor on micro- but not macrovascular endothelial cells may account for the reportedly different potency of TGF-beta 1 and TGF-beta 2 on these two endothelial cell types. Analysis of the 85 kDa and 65 kDa affinity-labeled bands revealed that all the endothelial cells express the Type II receptor and a band consistent with the presence of a dithiothreitol-sensitive Type I receptor. Two isoform-specific phosphoinositol-phospholipase C releasable TGF-beta binding proteins were also detected: a 60 kDa protein on one micro- (EJG) and one macro- (FBHE) vascular endothelial cell line and a 150/180 kDa protein on the macrovascular cell lines (FBHE and CPAE). These studies emphasize the heterogeneous nature of endothelial cells and underline the importance of using microvascular endothelial cells when examining TGF-beta responses related to microvascular function.

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Mapping of the ligand binding domain of the transforming growth factor beta receptor type III by deletion mutagenesis.

Cited by 38 publications

References 36 publications

Ligand Binding and Functional Properties of Betaglycan, a Co-receptor of the Transforming Growth Factor-β Superfamily

Ligand Binding and Functional Properties of Betaglycan, a Co-receptor of the Transforming Growth Factor-β Superfamily

Localization of N‐linked carbohydrate chains in glycoprotein ZPA of the bovine egg zona pellucida

Transforming growth factor‐β receptor expression on endothelial cells: Heterogeneity of type III receptor expression

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