WNT Activates the AAK1 Kinase to Promote Clathrin-Mediated Endocytosis of LRP6 and Establish a Negative Feedback Loop PMID: 30605688

ADC Targets in Oncology

2026-04-10

WNT Activates the AAK1 Kinase to Promote Clathrin-Mediated Endocytosis of LRP6 and Establish a Negative Feedback Loop

Cell Rep. 2019 Jan 2;26(1):79-93.e8. doi: 10.1016/j.celrep.2018.12.023.

Megan J Agajanian ¹ , Matthew P Walker ² , Alison D Axtman ³ , Roberta R Ruela-de-Sousa ⁴ , D Stephen Serafin ⁵ , Alex D Rabinowitz ² , David M Graham ⁶ , Meagan B Ryan ¹ , Tigist Tamir ¹ , Yuko Nakamichi ⁷ , Melissa V Gammons ⁸ , James M Bennett ⁹ , Rafael M Couñago ⁴ , David H Drewry ³ , Jonathan M Elkins ¹⁰ , Carina Gileadi ⁹ , Opher Gileadi ¹⁰ , Paulo H Godoi ⁴ , Nirav Kapadia ³ , Susanne Müller ¹¹ , André S Santiago ⁴ , Fiona J Sorrell ⁹ , Carrow I Wells ³ , Oleg Fedorov ⁹ , Timothy M Willson ³ , William J Zuercher ¹² , Michael B Major ¹³

Affiliations

1. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
2. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
3. Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
4. Structural Genomics Consortium, Universidade Estadual de Campinas - UNICAMP, Campinas, SP 13083-970, Brazil.
5. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
6. Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
7. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Institute for Oral Science, Matsumoto Dental University, Nagano 399-0704, Japan.
8. MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0SL, UK.
9. Structural Genomics Consortium and Target Discovery Institute, Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK.
10. Structural Genomics Consortium, Universidade Estadual de Campinas - UNICAMP, Campinas, SP 13083-970, Brazil; Structural Genomics Consortium and Target Discovery Institute, Nuffield Department of Clinical Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK.
11. Structural Genomics Consortium, Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main 60438, Germany.
12. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Structural Genomics Consortium, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
13. Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. Electronic address: [email protected].

Abstract

β-Catenin-dependent Wnt signal transduction governs development, tissue homeostasis, and a vast array of human diseases. Signal propagation through a WNT-Frizzled/LRP receptor complex requires proteins necessary for clathrin-mediated endocytosis (CME). Paradoxically, CME also negatively regulates Wnt signaling through internalization and degradation of the receptor complex. Here, using a gain-of-function screen of the human kinome, we report that the AP2 associated kinase 1 (AAK1), a known CME enhancer, inhibits Wnt signaling. Reciprocally, AAK1 genetic silencing or its pharmacological inhibition using a potent and selective inhibitor activates Wnt signaling. Mechanistically, we show that AAK1 promotes clearance of LRP6 from the plasma membrane to suppress the Wnt pathway. Time-course experiments support a transcription-uncoupled, WNT-driven negative feedback loop; prolonged Wnt treatment drives AAK1-dependent phosphorylation of AP2M1, clathrin-coated pit maturation, and endocytosis of LRP6. We propose that, following Wnt receptor activation, increased AAK1 function and CME limits Wnt signaling longevity.

Keywords

AAK1; AP2M1; LRP6; WNT signaling; clathrin; endocytosis; feedback loop; gain-of-function screen; kinase.