507.4 - Kinase Domain Autophosphorylation Rewires the Activity and Substrate Specificity of CK1 Enzymes

Sierra Cullati (Vanderbilt University), Apirat Chaikuad (Goethe University, Goethe University), Jun-Song Chen (Vanderbilt University), Jakob Gebel (Goethe University), Laura Tesmer (Max Planck Institute of Biophysics), Rezart Zhubi (Goethe University, Goethe University), Jose Navarrete-Perea (Harvard Medical School), Rodrigo Guillen (Vanderbilt University), Steven Gygi (Harvard Medical School), Gerhard Hummer (Max Planck Institute of Biophysics, Max Planck Institute of Biophysics), Volker Dotsch (Goethe University), Stefan Knapp (Goethe University, Goethe University), Kathleen Gould (Vanderbilt University)

CK1s are acidophilic serine/threonine kinases with multiple critical cellular functions; their misregulation contributes to cancer, neurodegenerative diseases, and sleep phase disorders. Here, we describe an evolutionarily conserved mechanism of CK1 activity: autophosphorylation of a threonine (T220 in human CK1δ) located at the N-terminus of helix αG, proximal to the substrate binding cleft. Crystal structures and molecular dynamics simulations uncovered inherent plasticity in αG that increased upon T220 autophosphorylation. The phosphorylation-induced structural changes significantly altered the conformation of the substrate binding cleft, affecting substrate specificity. In T220 phosphorylated yeast and human CK1s, activity toward many substrates was decreased, but we also identified a high-affinity substrate that was phosphorylated more rapidly, and quantitative phosphoproteomics revealed that disrupting T220 autophosphorylation rewired CK1 signaling in Schizosaccharomyces pombe. T220 is present exclusively in the CK1 family, thus its autophosphorylation may have evolved as a unique regulatory mechanism for this important family.

Support or Funding Information

S.N.C. was supported by the NIH Integrated Biological Systems Training in Oncology Program (T32 CA119925). S.K., A.C., and R.Z. are grateful for support by the SGC, a registered charity (no. 1097737) that receives funds from Bayer AG, Boehringer Ingelheim, Bristol Myers Squibb, Genentech, Genome Canada through Ontario Genomics Institute [OGI-196], EU/EFPIA/OICR/McGill/KTH/Diamond Innovative Medicines Initiative 2 Joint Undertaking [EUbOPEN grant 875510], Janssen, Merck KGaA (aka EMD in Canada and US), Pfizer and Takeda. J.G. and V.D. acknowledge support from the Deutsche Forschungsgemeinschaft (DO 545/18-1). This work was funded by NIH R35 GM131799 to K.L.G.