Abstract
Mutations affecting the transmembrane proteins Patched (Ptc) or Smoothened (Smo) that trigger ligand-independent activity of the Hedgehog (Hh) signalling pathway are associated with human tumours such as basal cell carcinoma (BCC) and medulloblastoma1,2,3. Despite extensive genetic studies demonstrating the importance of these receptor components in embryonic patterning and cancer, the mechanism by which Ptc regulates Smo is not understood4. Here we report that Ptc and Smo are not significantly associated within Hh-responsive cells. Furthermore, we show that free Ptc (unbound by Hh) acts sub-stoichiometrically to suppress Smo activity and thus is critical in specifying the level of pathway activity. Patched is a twelve-transmembrane protein with homology to bacterial proton-driven transmembrane molecular transporters; we demonstrate that the function of Ptc is impaired by alterations of residues that are conserved in and required for function of these bacterial transporters. These results suggest that the Ptc tumour suppressor functions normally as a transmembrane molecular transporter, which acts indirectly to inhibit Smo activity, possibly through changes in distribution or concentration of a small molecule.
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References
Bale, A. E. & Yu, K. P. The hedgehog pathway and basal cell carcinomas. Hum. Mol. Genet. 10, 757â762 (2001)
Wechsler-Reya, R. & Scott, M. P. The developmental biology of brain tumors. Annu. Rev. Neurosci. 24, 385â428 (2001)
Taipale, J. & Beachy, P. A. The Hedgehog and Wnt signalling pathways in cancer. Nature 411, 349â354 (2001)
Kalderon, D. Transducing the Hedgehog signal. Cell 103, 371â374 (2000)
Stone, D. M. et al. The tumour-suppressor gene patched encodes a candidate receptor for Sonic hedgehog. Nature 384, 129â134 (1996)
Fuse, N. et al. Sonic hedgehog protein signals not as a hydrolytic enzyme but as an apparent ligand for patched. Proc. Natl Acad. Sci. USA 96, 10992â10999 (1999)
Ingham, P. W., Taylor, A. M. & Nakano, Y. Role of Drosophila patched gene in positional signaling. Nature 353, 184â187 (1991)
Goodrich, L. V., Milenkovic, L., Higgins, K. M. & Scott, M. P. Altered neural cell fates and medulloblastoma in mouse patched mutants. Science 277, 1109â1113 (1997)
Ingham, P. W. & McMahon, A. P. Hedgehog signalling in animal development: paradigms and principles. Genes Dev. 15, 3059â3087 (2001)
Ingham, P. W. et al. Patched represses the Hedgehog signalling pathway by promoting modification of the Smoothened protein. Curr. Biol. 10, 1315â1318 (2000)
Denef, N., Neubuser, D., Perez, L. & Cohen, S. M. Hedgehog induces opposite changes in turnover and subcellular localization of patched and smoothened. Cell 102, 521â531 (2000)
Williams, K. P. et al. Functional antagonists of sonic hedgehog reveal the importance of the N terminus for activity. J. Cell. Sci. 112, 4405â4414 (1999)
Briscoe, J., Chen, Y., Jessell, T. M. & Struhl, G. A hedgehog-insensitive form of patched provides evidence for direct long-range morphogen activity of sonic hedgehog in the neural tube. Mol. Cell 7, 1279â1291 (2001)
Capdevila, J., Pariente, F., Sampedro, J., Alonso, J. L. & Guerrero, I. Subcellular localization of the segment polarity protein patched suggests an interaction with the wingless reception complex in Drosophila embryos. Development 120, 987â998 (1994)
Dann, C. E. et al. Insights into Wnt binding and signalling from the structures of two frizzled cysteine-rich domains. Nature 412, 86â90 (2001)
Alcedo, J., Zou, Y. & Noll, M. Posttranscriptional regulation of Smoothened is part of a self-correcting mechanism in the Hedgehog signaling system. Mol. Cell 6, 457â465 (2000)
Tseng, T. T. et al. The RND permease superfamily: an ancient, ubiquitous and diverse family that includes human disease and development proteins. J. Mol. Microbiol. Biotechnol. 1, 107â125 (1999)
Davies, J. P., Chen, F. W. & Ioannou, Y. A. Transmembrane molecular pump activity of niemann-pick C1 protein. Science 290, 2295â2298 (2000)
Burke, R. et al. Dispatched, a novel sterol sensing domain protein dedicated to the release of cholesterol-modified Hedgehog from signaling cells. Cell 99, 803â815 (1999)
Goldberg, M., Pribyl, T., Juhnke, S. & Nies, D. S. Energetics and topology of CzcA, a cation/proton antiporter of the resistance-nodulation-cell division protein family. J. Biol. Chem. 274, 26065â26070 (1999)
Guan, L. & Nakae, T. Identification of essential charged residues in transmembrane segments of the multidrug transporter MexB of Pseudomonas aeruginosa. J. Bacteriol. 183, 1734â1739 (2001)
Chidambaram, A. et al. Mutations in the human homologue of the Drosophila Patched gene in caucasian and African-American nevoid basal cell carcinoma syndrome patients. Cancer Res. 56, 4599â4601 (1996)
Wicking, C. et al. Most germ-line mutations in the nevoid basal cell carcinoma syndrome lead to premature termination of the Patched protein, and no genotypeâphenotype correlations are evident. Am. J. Hum. Genet. 60, 21â26 (1997)
Aszterbaum, M. et al. Identification of mutations in the human Patched gene in sporadic basal cell carcinomas and in patients with the basal cell nevus syndrome. J. Invest. Dermatol. 110, 885â888 (1998)
Taipale, J. et al. Effects of oncogenic mutations in Smoothened and Patched can be reversed by cyclopamine. Nature 406, 1005â1009 (2000)
Zeng, X. et al. A freely diffusible form of Sonic hedgehog mediates long range signalling. Nature 411, 716â720 (2001)
Sasaki, H., Hui, C.-c., Nakafuku, M. & Kondoh, H. A binding site for Gli proteins is essential for HNF3β floor plate enhancer activity in transgenics and can respond to Shh in vitro. Development 124, 1313â1322 (1997)
Strutt, H. et al. Mutations in the sterol-sensing domain of Patched suggest a role for vesicular trafficking in Smoothened regulation. Curr. Biol. 11, 608â613 (2001)
Martin, V., Carrillo, G., Torroja, C. & Guerrero, I. The sterol-sensing domain of Patched protein seems to control Smoothened activity through Patched vesicular trafficking. Curr. Biol. 11, 601â607 (2001)
Ko, D. C., Gordon, M. D., Jin, J. Y. & Scott, M. P. Dynamic movements of organelles containing Niemann-Pick C1 protein: NPC1 involvement in late endocytic events. Mol. Biol. Cell 12, 601â614 (2001)
Acknowledgements
We thank J. K. Chen, D. Ginty, D. Leahy, J. Nathans and G. Seydoux for critical review of the manuscript, and K. Young and R. Gong for technical assistance. P.A.B. is an investigator of the Howard Hughes Medical Institute. This work was supported by an NIH grant.
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Taipale, J., Cooper, M., Maiti, T. et al. Patched acts catalytically to suppress the activity of Smoothened. Nature 418, 892â896 (2002). https://doi.org/10.1038/nature00989
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DOI: https://doi.org/10.1038/nature00989