6nfy
From Proteopedia
Crystal structure of nonphosphorylated, HPK1 kinase domain in complex with sunitinib in the inactive state.
Structural highlights
Function[M4K1_HUMAN] Serine/threonine-protein kinase, which may play a role in the response to environmental stress. Appears to act upstream of the JUN N-terminal pathway. May play a role in hematopoietic lineage decisions and growth regulation. Able to autophosphorylate.[1] [2] Publication Abstract from PubMedHematopoietic 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 vitro 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 A resolutions. The native nonphosphorylated co-crystal 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. On the other hand, the phosphomimetic mutant co-crystal 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. Multiple conformational states of the HPK1 kinase domain in complex with sunitinib reveal the structural changes accompanying HPK1 trans-regulation.,Johnson E, McTigue M, Gallego RA, Johnson TW, Timofeevski S, Maestre M, Fisher TS, Kania R, Sawasdikosol S, Burakoff S, Cronin CN J Biol Chem. 2019 Apr 24. pii: AC119.007466. doi: 10.1074/jbc.AC119.007466. PMID:31018963[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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