Abstract
Mdm2 overexpression confers a growth promoting activity upon cells primarily by downregulating the p53 tumor suppressor protein. Nevertheless, Mdm2 deregulation has also been implicated in inhibiting TGF-β growth repression in a p53 independent manner. Our goal in this study was to examine whether overexpression of Mdm2 or MdmX, a Mdm2-related protein, could affect Smad-induced transactivation. As downstream signaling elements of the TGF-β pathway, Smads represent one potential target for Mdm2 and MdmX. Here we show that MdmX but not Mdm2 is capable of inhibiting Smad induced transactivation. Based on deletion mutant analysis, MdmX inhibition of Smad transactivation was independent of the p53 and Mdm2 interaction domains, yet required amino acid residues 128–444. Using TGF-β sensitive HepG2 cells, MdmX overexpression was shown to inhibit TGF-β induced Smad transactivation. Additionally, mouse embryo fibroblasts (MEFs) lacking p53 and MdmX showed enhanced Smad transactivation when compared to MEFs lacking either p53 or p53 and Mdm2. Interestingly, the inhibition of Smad transactivation by MdmX could be reversed by p300, a functional co-activator of Smads and a necessary factor for Mdm2 nuclear export and did not result from altered Smad localization. In vitro studies demonstrate that MdmX binds to p300 as well as Smad3 and Smad4. Taken together, these results suggest that inhibition of Smad-induced transactivation by MdmX occurs by altering Smad interaction with its coactivator p300.
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References
Akiyoshi S, Inoue H, Hanai J, Kusanagi K, Nemoto N, Miyazono K, Kawabata M . 1999 J. Biol. Chem. 274: 35269–35277
Blain S, Massague J . 2000 J. Biol. Chem. 275: 32066–32070
Brown T, Patil S, Basnett R, Howe P . 1998 Cell Growth Differ. 9: 869–875
Datta P, Blake M, Moses H . 2000 J. Biol. Chem. 275: 40014–4019
Datto M, Wang X . 2000 Cytokine Growth Factor Rev. 11: 37–48
de Caestecker M, Yahata T, Wang D, Parks W, Huang S, Hill C, Shioda T, Roberts A, Lechleider R . 2000 J. Biol. Chem. 275: 2115–2122
de Oca Luna R, Amelse L, Lozano G . 1997 Nature genetics 16: 336
Derynck R, Zhang Y, Feng X . 1998 Cell 95: 737–740
Feng X, Zhang Y, Wu R, Derynck R . 1998 Genes Dev. 12: 2153–2163
Finch RA, Donoviel DB, Potter D, Shi M, Fan A, Freed DD, Wang CY, Zambrowicz BP, Ramirez-Solis R, Sands AT, Zhang N . 2002 Cancer Res. 62: 3221–3225
Giordano A, Avantaggiati M . 1999 J. Cell Physiol. 181: 218–230
Grossman S, Perez M, Kung A, Joseph M, Mansur C, Xiao Z, Kumar S, Howley P, Livingston D . 1998 Mol. Cell 2: 405–415
Haupt Y, Maya R, Kazaz A, Oren M . 1997 Nature 387: 296–299
Ivarone A, Massague J . 1999 Mol. Cell Biol. 19: 916–922
Jackson M, Berberich S . 1999 DNA Cell Biol. 18: 693–700
Jackson M, Berberich S . 2000 Mol. Cell. Biol. 20: 1001–1007
Jackson M, Lindstrom M, Berberich S . 2001 J. Biol. Chem. 10: 10
Kadakia M, Slader C, Berberich S . 2001 DNA Cell Biol. 20: 321–330
Kim R, Wang D, Tsang M, Martin J, Huff C, de Caestecker M, Parks W, Meng X, Lechleider R, Wang T, Roberts A . 2000 Genes Dev. 14: 1605–1616
Kubbutat M, Jones S, Vousden K . 1997 Nature 387: 299–303
Levine A . 1997 Cell 88: 323–331
Lundgren K, Montes de Oca Luna R, McNeill Y, Emerick E, Spencer B, Barfield C, Lozano G, Rosenberg M, Finlay C . 1997 Genes Dev. 11: 714–725
Massague J . 1998 Annu. Rev. Biochem. 67: 753–791
Massague J, Blain S, Lo R . 2000 Cell 103: 295–309
Migliorini D, Denchi EL, Danovi D, Jochemsen A, Capillo M, Gobbi A, Helin K, Pelicci PG, Marine JC . 2002 Mol. Cell. Biol. 22: 5527–5538
Parant J, Chavez-Reyes A, Little N, Yan W, Reinke V, Jochemsen A, Lozano G . 2001 Nat. Genet. 29: 92–95
Penttinen R, Kobayashi S, Bornstein P . 1988 Proc. Natl. Acad. Sci. USA 85: 1105–1108
Piek E, Heldin C, Ten Dijke P . 1999 FASEB J. 13: 2105–2124
Pouponnot C, Jayaraman L, Massague J . 1998 J. Biol. Chem. 273: 22865–22868
Sandler M, Zhang J, Westerhausen Jr D, Billadello J . 1994 J. Biol. Chem. 269: 21500–21504
Shen X, Hu P, Liberati N, Datto M, Frederick J, Wang X . 1998 Mol. Biol. Cell. 9: 3309–3319
Shvarts A, Steegenga W, Riteco N, van Laar T, Dekker P, Bazuine M, van Ham R, van der Houven van Oordt W, Hateboer G, van der Eb A, Jochemsen A . 1996 EMBO J. 15: 5349–5357
Sun P, Dong P, Dai K, Hannon G, Beach D . 1998 Science 282: 2270–2272
Tanimura S, Ohtsuka S, Mitsui K, Shirouzu K, Yoshimura A, Ohtsubo M . 1999 FEBS Lett. 447: 5–9
Teruel T, Valverde A, Benito M, Lorenzo M . 1995 FEBS Lett. 364: 193–197
Thomas A, White E . 1998 Genes Dev. 12: 1975–1985
Warner G, Ludlow J, Nelson D, Gaur A, Scott D . 1992 Cell Growth Differ. 3: 175–181
Wrana J . 2000 Cell 100: 189–192
Wrana J, Attisano L . 2000 Cytokine Growth Factor Rev. 11: 5–13
Yam C, Siu W, Arooz T, Chiu C, Lau A, Wang X, Poon R . 1999 Cancer Res. 59: 5075–5078
Zhu Q, Yao J, Wani G, Wani M, Wani A . 2001 J. Biol. Chem. 276: 29695–29701
Acknowledgements
We would like to thank Steve Ledbetter and Genzyme, Inc. for providing the TGF beta and Andrea Myers for technical assistance. M Kadakia was supported by a postdoctoral fellowship from the Wright State University School of Medicine. This work is supported by a NIH grant (CA64430) to SJ Berberich.
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