Skip to main content
PMC home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1996 Jun 1;133(5):1109–1121. doi: 10.1083/jcb.133.5.1109

Endoglin modulates cellular responses to TGF-beta 1

PMCID: PMC2120857  PMID: 8655583

Abstract

Endoglin is a homodimeric membrane glycoprotein which can bind the beta 1 and beta 3 isoforms of transforming growth factor-beta (TGF-beta). We reported previously that endoglin is upregulated during monocyte differentiation. We have now observed that TGF-beta itself can stimulate the expression of endoglin in cultured human monocytes and in the U-937 monocytic line. To study the functional role of endoglin, stable transfectants of U-937 cells were generated which overexpress L- or S- endoglin isoforms, differing in their cytoplasmic domain. Inhibition of cellular proliferation and downregulation of c-myc mRNA which are normally induced by TGF-beta 1 in U-937 cells were totally abrogated in L-endoglin transfectants and much reduced in the S- endoglin transfectants. Inhibition of proliferation by TGF-beta 2 was not altered in the transfectants, in agreement with the isoform specificity of endoglin. Additional responses of U-937 cells to TGF- beta 1, including stimulation of fibronectin synthesis, cellular adhesion, platelet/endothelial cell adhesion molecule 1 (PECAM-1) phosphorylation, and homotypic aggregation were also inhibited in the endoglin transfectants. However, modulation of integrin and PECAM-1 levels and stimulation of mRNA levels for TGF-beta 1 and its receptors R-I, R-II, and betaglycan occurred normally in the endoglin transfectants. No changes in total ligand binding were observed in L- endoglin transfectants relative to mock, while a 1.5-fold increase was seen in S-endoglin transfectants. The degradation rate of the ligand was the same in all transfectants. Elucidating the mechanism by which endoglin modulates several cellular responses to TGF-beta 1 without interfering with ligand binding or degradation should increase our understanding of the complex pathways which mediate the effects of this factor.

Full Text

The Full Text of this article is available as a PDF (2.0 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Alexandrow M. G., Kawabata M., Aakre M., Moses H. L. Overexpression of the c-Myc oncoprotein blocks the growth-inhibitory response but is required for the mitogenic effects of transforming growth factor beta 1. Proc Natl Acad Sci U S A. 1995 Apr 11;92(8):3239–3243. doi: 10.1073/pnas.92.8.3239. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Assoian R. K., Fleurdelys B. E., Stevenson H. C., Miller P. J., Madtes D. K., Raines E. W., Ross R., Sporn M. B. Expression and secretion of type beta transforming growth factor by activated human macrophages. Proc Natl Acad Sci U S A. 1987 Sep;84(17):6020–6024. doi: 10.1073/pnas.84.17.6020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Attisano L., Wrana J. L., López-Casillas F., Massagué J. TGF-beta receptors and actions. Biochim Biophys Acta. 1994 May 26;1222(1):71–80. doi: 10.1016/0167-4889(94)90026-4. [DOI] [PubMed] [Google Scholar]
  4. Bassing C. H., Yingling J. M., Howe D. J., Wang T., He W. W., Gustafson M. L., Shah P., Donahoe P. K., Wang X. F. A transforming growth factor beta type I receptor that signals to activate gene expression. Science. 1994 Jan 7;263(5143):87–89. doi: 10.1126/science.8272871. [DOI] [PubMed] [Google Scholar]
  5. Bauvois B., Rouillard D., Sanceau J., Wietzerbin J. IFN-gamma and transforming growth factor-beta 1 differently regulate fibronectin and laminin receptors of human differentiating monocytic cells. J Immunol. 1992 Jun 15;148(12):3912–3919. [PubMed] [Google Scholar]
  6. Bellón T., Corbí A., Lastres P., Calés C., Cebrián M., Vera S., Cheifetz S., Massague J., Letarte M., Bernabéu C. Identification and expression of two forms of the human transforming growth factor-beta-binding protein endoglin with distinct cytoplasmic regions. Eur J Immunol. 1993 Sep;23(9):2340–2345. doi: 10.1002/eji.1830230943. [DOI] [PubMed] [Google Scholar]
  7. Bühring H. J., Müller C. A., Letarte M., Gougos A., Saalmüller A., van Agthoven A. J., Busch F. W. Endoglin is expressed on a subpopulation of immature erythroid cells of normal human bone marrow. Leukemia. 1991 Oct;5(10):841–847. [PubMed] [Google Scholar]
  8. Cabañas C., Sanchez-Madrid F., Bellon T., Figdor C. G., Te Velde A. A., Fernandez J. M., Acevedo A., Bernabeu C. Characterization of a novel myeloid antigen regulated during differentiation of monocytic cells. Eur J Immunol. 1989 Aug;19(8):1373–1378. doi: 10.1002/eji.1830190804. [DOI] [PubMed] [Google Scholar]
  9. Cheifetz S., Bellón T., Calés C., Vera S., Bernabeu C., Massagué J., Letarte M. Endoglin is a component of the transforming growth factor-beta receptor system in human endothelial cells. J Biol Chem. 1992 Sep 25;267(27):19027–19030. [PubMed] [Google Scholar]
  10. Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
  11. Cárcamo J., Weis F. M., Ventura F., Wieser R., Wrana J. L., Attisano L., Massagué J. Type I receptors specify growth-inhibitory and transcriptional responses to transforming growth factor beta and activin. Mol Cell Biol. 1994 Jun;14(6):3810–3821. doi: 10.1128/mcb.14.6.3810. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Dalla-Favera R., Gelmann E. P., Martinotti S., Franchini G., Papas T. S., Gallo R. C., Wong-Staal F. Cloning and characterization of different human sequences related to the onc gene (v-myc) of avian myelocytomatosis virus (MC29). Proc Natl Acad Sci U S A. 1982 Nov;79(21):6497–6501. doi: 10.1073/pnas.79.21.6497. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. De Benedetti F., Falk L. A., Ellingsworth L. R., Ruscetti F. W., Faltynek C. R. Synergy between transforming growth factor-beta and tumor necrosis factor-alpha in the induction of monocytic differentiation of human leukemic cell lines. Blood. 1990 Feb 1;75(3):626–632. [PubMed] [Google Scholar]
  14. Fernández-Ruiz E., St-Jacques S., Bellón T., Letarte M., Bernabéu C. Assignment of the human endoglin gene (END) to 9q34-->qter. Cytogenet Cell Genet. 1993;64(3-4):204–207. doi: 10.1159/000133576. [DOI] [PubMed] [Google Scholar]
  15. Franzén P., ten Dijke P., Ichijo H., Yamashita H., Schulz P., Heldin C. H., Miyazono K. Cloning of a TGF beta type I receptor that forms a heteromeric complex with the TGF beta type II receptor. Cell. 1993 Nov 19;75(4):681–692. doi: 10.1016/0092-8674(93)90489-d. [DOI] [PubMed] [Google Scholar]
  16. Frolik C. A., Wakefield L. M., Smith D. M., Sporn M. B. Characterization of a membrane receptor for transforming growth factor-beta in normal rat kidney fibroblasts. J Biol Chem. 1984 Sep 10;259(17):10995–11000. [PubMed] [Google Scholar]
  17. Gougos A., Letarte M. Identification of a human endothelial cell antigen with monoclonal antibody 44G4 produced against a pre-B leukemic cell line. J Immunol. 1988 Sep 15;141(6):1925–1933. [PubMed] [Google Scholar]
  18. Gougos A., Letarte M. Primary structure of endoglin, an RGD-containing glycoprotein of human endothelial cells. J Biol Chem. 1990 May 25;265(15):8361–8364. [PubMed] [Google Scholar]
  19. Gougos A., St Jacques S., Greaves A., O'Connell P. J., d'Apice A. J., Bühring H. J., Bernabeu C., van Mourik J. A., Letarte M. Identification of distinct epitopes of endoglin, an RGD-containing glycoprotein of endothelial cells, leukemic cells, and syncytiotrophoblasts. Int Immunol. 1992 Jan;4(1):83–92. doi: 10.1093/intimm/4.1.83. [DOI] [PubMed] [Google Scholar]
  20. Jindal S. K., Ishii E., Letarte M., Vera S., Teerds K. J., Dorrington J. H. Regulation of transforming growth factor alpha gene expression in an ovarian surface epithelial cell line derived from a human carcinoma. Biol Reprod. 1995 May;52(5):1027–1037. doi: 10.1095/biolreprod52.5.1027. [DOI] [PubMed] [Google Scholar]
  21. Kingsley D. M. The TGF-beta superfamily: new members, new receptors, and new genetic tests of function in different organisms. Genes Dev. 1994 Jan;8(2):133–146. doi: 10.1101/gad.8.2.133. [DOI] [PubMed] [Google Scholar]
  22. Koenig B. B., Cook J. S., Wolsing D. H., Ting J., Tiesman J. P., Correa P. E., Olson C. A., Pecquet A. L., Ventura F., Grant R. A. Characterization and cloning of a receptor for BMP-2 and BMP-4 from NIH 3T3 cells. Mol Cell Biol. 1994 Sep;14(9):5961–5974. doi: 10.1128/mcb.14.9.5961. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Laiho M., Weis F. M., Boyd F. T., Ignotz R. A., Massagué J. Responsiveness to transforming growth factor-beta (TGF-beta) restored by genetic complementation between cells defective in TGF-beta receptors I and II. J Biol Chem. 1991 May 15;266(14):9108–9112. [PubMed] [Google Scholar]
  24. Lastres P., Almendro N., Bellón T., López-Guerrero J. A., Eritja R., Bernabéu C. Functional regulation of platelet/endothelial cell adhesion molecule-1 by TGF-beta 1 in promonocytic U-937 cells. J Immunol. 1994 Nov 1;153(9):4206–4218. [PubMed] [Google Scholar]
  25. Lastres P., Bellon T., Cabañas C., Sanchez-Madrid F., Acevedo A., Gougos A., Letarte M., Bernabeu C. Regulated expression on human macrophages of endoglin, an Arg-Gly-Asp-containing surface antigen. Eur J Immunol. 1992 Feb;22(2):393–397. doi: 10.1002/eji.1830220216. [DOI] [PubMed] [Google Scholar]
  26. Lastres P., Martín-Perez J., Langa C., Bernabéu C. Phosphorylation of the human-transforming-growth-factor-beta-binding protein endoglin. Biochem J. 1994 Aug 1;301(Pt 3):765–768. doi: 10.1042/bj3010765. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Lin H. Y., Wang X. F., Ng-Eaton E., Weinberg R. A., Lodish H. F. Expression cloning of the TGF-beta type II receptor, a functional transmembrane serine/threonine kinase. Cell. 1992 Feb 21;68(4):775–785. doi: 10.1016/0092-8674(92)90152-3. [DOI] [PubMed] [Google Scholar]
  28. López-Casillas F., Cheifetz S., Doody J., Andres J. L., Lane W. S., Massagué J. Structure and expression of the membrane proteoglycan betaglycan, a component of the TGF-beta receptor system. Cell. 1991 Nov 15;67(4):785–795. doi: 10.1016/0092-8674(91)90073-8. [DOI] [PubMed] [Google Scholar]
  29. López-Casillas F., Payne H. M., Andres J. L., Massagué J. Betaglycan can act as a dual modulator of TGF-beta access to signaling receptors: mapping of ligand binding and GAG attachment sites. J Cell Biol. 1994 Feb;124(4):557–568. doi: 10.1083/jcb.124.4.557. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. López-Casillas F., Wrana J. L., Massagué J. Betaglycan presents ligand to the TGF beta signaling receptor. Cell. 1993 Jul 2;73(7):1435–1444. doi: 10.1016/0092-8674(93)90368-z. [DOI] [PubMed] [Google Scholar]
  31. Massagué J., Attisano L., Wrana J. L. The TGF-beta family and its composite receptors. Trends Cell Biol. 1994 May;4(5):172–178. doi: 10.1016/0962-8924(94)90202-x. [DOI] [PubMed] [Google Scholar]
  32. McAllister K. A., Grogg K. M., Johnson D. W., Gallione C. J., Baldwin M. A., Jackson C. E., Helmbold E. A., Markel D. S., McKinnon W. C., Murrell J. Endoglin, a TGF-beta binding protein of endothelial cells, is the gene for hereditary haemorrhagic telangiectasia type 1. Nat Genet. 1994 Dec;8(4):345–351. doi: 10.1038/ng1294-345. [DOI] [PubMed] [Google Scholar]
  33. McCartney-Francis N., Mizel D., Wong H., Wahl L., Wahl S. TGF-beta regulates production of growth factors and TGF-beta by human peripheral blood monocytes. Growth Factors. 1990;4(1):27–35. doi: 10.3109/08977199009011007. [DOI] [PubMed] [Google Scholar]
  34. Miyazono K., Ten Dijke P., Ichijo H., Heldin C. H. Receptors for transforming growth factor-beta. Adv Immunol. 1994;55:181–220. [PubMed] [Google Scholar]
  35. Morén A., Ichijo H., Miyazono K. Molecular cloning and characterization of the human and porcine transforming growth factor-beta type III receptors. Biochem Biophys Res Commun. 1992 Nov 30;189(1):356–362. doi: 10.1016/0006-291x(92)91566-9. [DOI] [PubMed] [Google Scholar]
  36. Moses H. L., Yang E. Y., Pietenpol J. A. TGF-beta stimulation and inhibition of cell proliferation: new mechanistic insights. Cell. 1990 Oct 19;63(2):245–247. doi: 10.1016/0092-8674(90)90155-8. [DOI] [PubMed] [Google Scholar]
  37. Moustakas A., Lin H. Y., Henis Y. I., Plamondon J., O'Connor-McCourt M. D., Lodish H. F. The transforming growth factor beta receptors types I, II, and III form hetero-oligomeric complexes in the presence of ligand. J Biol Chem. 1993 Oct 25;268(30):22215–22218. [PubMed] [Google Scholar]
  38. Murphy L. D., Herzog C. E., Rudick J. B., Fojo A. T., Bates S. E. Use of the polymerase chain reaction in the quantitation of mdr-1 gene expression. Biochemistry. 1990 Nov 13;29(45):10351–10356. doi: 10.1021/bi00497a009. [DOI] [PubMed] [Google Scholar]
  39. O'Connell P. J., McKenzie A., Fisicaro N., Rockman S. P., Pearse M. J., d'Apice A. J. Endoglin: a 180-kD endothelial cell and macrophage restricted differentiation molecule. Clin Exp Immunol. 1992 Oct;90(1):154–159. doi: 10.1111/j.1365-2249.1992.tb05848.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Roberts A. B., Sporn M. B. Physiological actions and clinical applications of transforming growth factor-beta (TGF-beta). Growth Factors. 1993;8(1):1–9. doi: 10.3109/08977199309029129. [DOI] [PubMed] [Google Scholar]
  41. Rokhlin O. W., Cohen M. B., Kubagawa H., Letarte M., Cooper M. D. Differential expression of endoglin on fetal and adult hematopoietic cells in human bone marrow. J Immunol. 1995 May 1;154(9):4456–4465. [PubMed] [Google Scholar]
  42. St-Jacques S., Cymerman U., Pece N., Letarte M. Molecular characterization and in situ localization of murine endoglin reveal that it is a transforming growth factor-beta binding protein of endothelial and stromal cells. Endocrinology. 1994 Jun;134(6):2645–2657. doi: 10.1210/endo.134.6.8194490. [DOI] [PubMed] [Google Scholar]
  43. Sánchez-Madrid F., De Landázuri M. O., Morago G., Cebrián M., Acevedo A., Bernabeu C. VLA-3: a novel polypeptide association within the VLA molecular complex: cell distribution and biochemical characterization. Eur J Immunol. 1986 Nov;16(11):1343–1349. doi: 10.1002/eji.1830161106. [DOI] [PubMed] [Google Scholar]
  44. Testa U., Masciulli R., Tritarelli E., Pustorino R., Mariani G., Martucci R., Barberi T., Camagna A., Valtieri M., Peschle C. Transforming growth factor-beta potentiates vitamin D3-induced terminal monocytic differentiation of human leukemic cell lines. J Immunol. 1993 Mar 15;150(6):2418–2430. [PubMed] [Google Scholar]
  45. Wahl S. M., Allen J. B., Weeks B. S., Wong H. L., Klotman P. E. Transforming growth factor beta enhances integrin expression and type IV collagenase secretion in human monocytes. Proc Natl Acad Sci U S A. 1993 May 15;90(10):4577–4581. doi: 10.1073/pnas.90.10.4577. [DOI] [PMC free article] [PubMed] [Google Scholar]
  46. Wahl S. M., Hunt D. A., Wakefield L. M., McCartney-Francis N., Wahl L. M., Roberts A. B., Sporn M. B. Transforming growth factor type beta induces monocyte chemotaxis and growth factor production. Proc Natl Acad Sci U S A. 1987 Aug;84(16):5788–5792. doi: 10.1073/pnas.84.16.5788. [DOI] [PMC free article] [PubMed] [Google Scholar]
  47. Wahl S. M. Transforming growth factor beta: the good, the bad, and the ugly. J Exp Med. 1994 Nov 1;180(5):1587–1590. doi: 10.1084/jem.180.5.1587. [DOI] [PMC free article] [PubMed] [Google Scholar]
  48. Wang X. F., Lin H. Y., Ng-Eaton E., Downward J., Lodish H. F., Weinberg R. A. Expression cloning and characterization of the TGF-beta type III receptor. Cell. 1991 Nov 15;67(4):797–805. doi: 10.1016/0092-8674(91)90074-9. [DOI] [PubMed] [Google Scholar]
  49. Wrana J. L., Attisano L., Cárcamo J., Zentella A., Doody J., Laiho M., Wang X. F., Massagué J. TGF beta signals through a heteromeric protein kinase receptor complex. Cell. 1992 Dec 11;71(6):1003–1014. doi: 10.1016/0092-8674(92)90395-s. [DOI] [PubMed] [Google Scholar]
  50. Wrana J. L., Attisano L., Wieser R., Ventura F., Massagué J. Mechanism of activation of the TGF-beta receptor. Nature. 1994 Aug 4;370(6488):341–347. doi: 10.1038/370341a0. [DOI] [PubMed] [Google Scholar]
  51. Yamashita H., Ichijo H., Grimsby S., Morén A., ten Dijke P., Miyazono K. Endoglin forms a heteromeric complex with the signaling receptors for transforming growth factor-beta. J Biol Chem. 1994 Jan 21;269(3):1995–2001. [PubMed] [Google Scholar]
  52. Yingling J. M., Wang X. F., Bassing C. H. Signaling by the transforming growth factor-beta receptors. Biochim Biophys Acta. 1995 Dec 18;1242(2):115–136. doi: 10.1016/0304-419x(95)00007-2. [DOI] [PubMed] [Google Scholar]
  53. Zhang H., Shaw A. R., Mak A., Letarte M. Endoglin is a component of the transforming growth factor (TGF)-beta receptor complex of human pre-B leukemic cells. J Immunol. 1996 Jan 15;156(2):564–573. [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES