Multiple conformational states of the HPK1 kinase domain in complex with sunitinib reveal the structural changes accompanying HPK1 trans-regulation.
Eric Johnson, Michele McTigue, Rebecca A Gallego, Ted W Johnson, Sergei Timofeevski, Michael Maestre, Timothy S Fisher, Robert Kania, Sansana Sawasdikosol, Steven Burakoff, Ciarán N Cronin
Author Information
Eric Johnson: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and. ORCID
Michele McTigue: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Rebecca A Gallego: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Ted W Johnson: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Sergei Timofeevski: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Michael Maestre: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Timothy S Fisher: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Robert Kania: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and.
Sansana Sawasdikosol: Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029.
Steven Burakoff: Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029.
Ciarán N Cronin: From the La Jolla Laboratories, Pfizer Worldwide Research and Development, San Diego, California 92121 and ciaran.cronin@pfizer.com. ORCID
Hematopoietic progenitor kinase 1 (HPK1 or MAP4K1) is a Ser/Thr kinase that operates via the c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) signaling pathways to dampen the T-cell response and antitumor immunity. Accordingly, selective HPK1 inhibition is considered a means to enhance antitumor immunity. sunitinib, a multi-receptor tyrosine kinase (RTK) inhibitor approved for the management of gastrointestinal stromal tumors (GISTs), renal cell carcinoma (RCC), and pancreatic cancer, has been reported to inhibit HPK1 In this report, we describe the crystal structures of the native HPK1 kinase domain in both nonphosphorylated and doubly phosphorylated states, in addition to a double phosphomimetic mutant (T165E,S171E), each complexed with sunitinib at 2.17-3.00-Å resolutions. The native nonphosphorylated cocrystal structure revealed an inactive dimer in which the activation loop of each monomer partially occupies the ATP- and substrate-binding sites of the partner monomer. In contrast, the structure of the protein with a doubly phosphorylated activation loop exhibited an active kinase conformation with a greatly reduced monomer-monomer interface. Conversely, the phosphomimetic mutant cocrystal structure disclosed an alternative arrangement in which the activation loops are in an extended domain-swapped configuration. These structural results indicate that HPK1 is a highly dynamic kinase that undergoes trans-regulation via dimer formation and extensive intramolecular and intermolecular remodeling of the activation segment.
