Abstract
The Hedgehog (Hh) cascade is central to development, tissue homeostasis and cancer. A pivotal step in Hh signal transduction is the activation of glioma-associated (GLI) transcription factors by the atypical G protein-coupled receptor (GPCR) SMOOTHENED (SMO). How SMO activates GLI remains unclear. Here we show that SMO uses a decoy substrate sequence to physically block the active site of the cAMP-dependent protein kinase (PKA) catalytic subunit (PKA-C) and extinguish its enzymatic activity. As a result, GLI is released from phosphorylation-induced inhibition. Using a combination of in vitro, cellular and organismal models, we demonstrate that interfering with SMO-PKA pseudosubstrate interactions prevents Hh signal transduction. The mechanism uncovered echoes one used by the Wnt cascade, revealing an unexpected similarity in how these two essential developmental and cancer pathways signal intracellularly. More broadly, our findings define a mode of GPCR-PKA communication that may be harnessed by a range of membrane receptors and kinases.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 990-999 |
| Number of pages | 10 |
| Journal | Nature Structural and Molecular Biology |
| Volume | 29 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2022 |
Bibliographical note
Funding Information:We thank J. Zalatan for making us aware of the parallels between SMO/PKA-C regulation in the Hh pathway and LRP/GSK-3β regulation in the Wnt pathway. We thank S. Lusk and K. Kwan (University of Utah) for providing smo-null zebrafish (smo), and D. Klatt Shaw and D. Grunwald (University of Utah) for sharing advice and reagents regarding zebrafish immunohistochemistry. We thank J. Müller and S. Kasten (University of Kassel) for excellent technical assistance. We thank the Johnson Foundation Structural Biology and Biophysics Core at the Perelman School of Medicine (University of Pennsylvania, Philadelphia, PA, USA) for performing multi-angle light scattering coupled with size-exclusion chromatography analyses. We thank D. Julius, S. Nakielny, A. Manglik, K. Basham and M. He for providing feedback on the manuscript. B.R.M. acknowledges support from the 5 for the Fight Foundation (award no. 6000-32705) and a Cancer Center Support Grant Pilot Project Fund from the Huntsman Cancer Institute (award no. 200206). This work was supported by the DFG (the German Research Foundation) grant no. GRK2749/1 (F.W.H.) and National Institutes of Health grant nos. R01GM100310-08 (G.V.), 1R35GM130389 (S.S.T.), 1R03TR002947 (S.S.T.) and 1R35GM133672 (B.R.M.). hi1640
Funding Information:
We thank J. Zalatan for making us aware of the parallels between SMO/PKA-C regulation in the Hh pathway and LRP/GSK-3β regulation in the Wnt pathway. We thank S. Lusk and K. Kwan (University of Utah) for providing smo- null zebrafish (smohi1640), and D. Klatt Shaw and D. Grunwald (University of Utah) for sharing advice and reagents regarding zebrafish immunohistochemistry. We thank J. Müller and S. Kasten (University of Kassel) for excellent technical assistance. We thank the Johnson Foundation Structural Biology and Biophysics Core at the Perelman School of Medicine (University of Pennsylvania, Philadelphia, PA, USA) for performing multi-angle light scattering coupled with size-exclusion chromatography analyses. We thank D. Julius, S. Nakielny, A. Manglik, K. Basham and M. He for providing feedback on the manuscript. B.R.M. acknowledges support from the 5 for the Fight Foundation (award no. 6000-32705) and a Cancer Center Support Grant Pilot Project Fund from the Huntsman Cancer Institute (award no. 200206). This work was supported by the DFG (the German Research Foundation) grant no. GRK2749/1 (F.W.H.) and National Institutes of Health grant nos. R01GM100310-08 (G.V.), 1R35GM130389 (S.S.T.), 1R03TR002947 (S.S.T.) and 1R35GM133672 (B.R.M.).
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature America, Inc.
