AAK1 inhibits WNT signaling by promoting clathrin-mediated endocytosis of LRP6

Agajanian, M.; Walker, M.; Axtman, A.; Ruela-de-Sousa, R.; Rabinowitz, A.; Graham, D.; Ryan, M.; Serafin, S.; Bennett, J.; Counago, R.; Drewry, D.; Elkins, J.; Gileadi, C.; Gileadi, O.; Godoi, P.; Kapadia, N.; Muller, S.; Santiago, A.; Sorrell, F.; Wells, C.; Fedorov, O.; Willson, T.; Zuercher, W.; Major, M. B.

doi:10.1101/258632

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bioRxiv · 10.1101/258632

AAK1 inhibits WNT signaling by promoting clathrin-mediated endocytosis of LRP6

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Abstract

{beta}-catenin-dependent WNT signal transduction governs normal development and adult tissue homeostasis. Inappropriate pathway activity mediates a vast array of human diseases, including bone density disorders, neurodegeneration and cancer. Although several WNT-directed therapeutics are in clinical trials, new targets, compounds and strategies are needed. We performed a gain-of-function screen of the human kinome to identify new druggable regulators of {beta}-catenin-dependent transcription. We found that over-expression of the AP2 Associated Kinase 1 (AAK1) strongly inhibited WNT signaling. Reciprocally, silencing of AAK1 expression or pharmacological inhibition of AAK1 kinase activity using a new, selective and potent small molecule inhibitor activated WNT signaling. This small molecule is a cell active dual AAK1/BMP2K inhibitor that represents the best available tool to study AAK1-dependent signaling pathways. We report that AAK1 and the WNT co-receptor LRP6 physically co-complex and that AAK1 promotes clathrin-mediated endocytosis of LRP6. Collectively, our data support a WNT-induced negative feedback loop mediated by AAK1-driven, clathrin-mediated endocytosis of LRP6.\n\nSummary StatementA gain-of-function screen of the human kinome revealed AAK1 as a negative regulator of WNT signaling. We show that AAK1 promotes clathrin-mediated endocytosis of LRP6, resulting in downregulation of WNT signaling. We use a new selective and potent AAK1/BMP2K small molecule probe to validate our findings.

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Agajanian, M., Walker, M., Axtman, A., Ruela-de-Sousa, R., Rabinowitz, A., Graham, D., Ryan, M., Serafin, S., Bennett, J., Counago, R., Drewry, D., Elkins, J., Gileadi, C., Gileadi, O., Godoi, P., Kapadia, N., Muller, S., Santiago, A., Sorrell, F., Wells, C., Fedorov, O., Willson, T., Zuercher, W., Major, M. B.. 2018-02-01. AAK1 inhibits WNT signaling by promoting clathrin-mediated endocytosis of LRP6. https://doi.org/10.1101/258632

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