6ny4
Crystal structure of JAK3 kinase domain in complex with a pyrrolopyridazine carboxamide inhibitorCrystal structure of JAK3 kinase domain in complex with a pyrrolopyridazine carboxamide inhibitor
Structural highlights
Disease[JAK3_HUMAN] Defects in JAK3 are a cause of severe combined immunodeficiency autosomal recessive T-cell-negative/B-cell-positive/NK-cell-negative (T(-)B(+)NK(-) SCID) [MIM:600802]. A form of severe combined immunodeficiency (SCID), a genetically and clinically heterogeneous group of rare congenital disorders characterized by impairment of both humoral and cell-mediated immunity, leukopenia, and low or absent antibody levels. Patients present in infancy recurrent, persistent infections by opportunistic organisms. The common characteristic of all types of SCID is absence of T-cell-mediated cellular immunity due to a defect in T-cell development.[1] [2] [3] [:][4] [5] [6] [7] [8] Function[JAK3_HUMAN] Non-receptor tyrosine kinase involved in various processes such as cell growth, development, or differentiation. Mediates essential signaling events in both innate and adaptive immunity and plays a crucial role in hematopoiesis during T-cells development. In the cytoplasm, plays a pivotal role in signal transduction via its association with type I receptors sharing the common subunit gamma such as IL2R, IL4R, IL7R, IL9R, IL15R and IL21R. Following ligand binding to cell surface receptors, phosphorylates specific tyrosine residues on the cytoplasmic tails of the receptor, creating docking sites for STATs proteins. Subsequently, phosphorylates the STATs proteins once they are recruited to the receptor. Phosphorylated STATs then form homodimer or heterodimers and translocate to the nucleus to activate gene transcription. For example, upon IL2R activation by IL2, JAK1 and JAK3 molecules bind to IL2R beta (IL2RB) and gamma chain (IL2RG) subunits inducing the tyrosine phosphorylation of both receptor subunits on their cytoplasmic domain. Then, STAT5A AND STAT5B are recruited, phosphorylated and activated by JAK1 and JAK3. Once activated, dimerized STAT5 translocates to the nucleus and promotes the transcription of specific target genes in a cytokine-specific fashion.[9] [10] [11] Publication Abstract from PubMedThe four members of the Janus family of nonreceptor tyrosine kinases play a significant role in immune function. The JAK family kinase inhibitor, tofacitinib 1, has been approved in the United States for use in rheumatoid arthritis (RA) patients. A number of JAK inhibitors with a variety of JAK family selectivity profiles are currently in clinical trials. Our goal was to identify inhibitors that were functionally selective for JAK1 and JAK3. Compound 22 was prepared with the desired functional selectivity profile, but it suffered from poor absorption related to physical properties. Use of the phosphate prodrug 32 enabled progression to a murine collagen induced arthritis (CIA) model. The demonstration of a robust efficacy in the CIA model suggests that use of phosphate prodrugs may resolve issues with progressing this chemotype for the treatment of autoimmune diseases such as RA. Discovery of a JAK1/3 Inhibitor and Use of a Prodrug To Demonstrate Efficacy in a Model of Rheumatoid Arthritis.,Spergel SH, Mertzman ME, Kempson J, Guo J, Stachura S, Haque L, Lippy JS, Zhang RF, Galella M, Pitt S, Shen G, Fura A, Gillooly K, McIntyre KW, Tang V, Tokarski J, Sack JS, Khan J, Carter PH, Barrish JC, Nadler SG, Salter-Cid LM, Schieven GL, Wrobleski ST, Pitts WJ ACS Med Chem Lett. 2019 Feb 13;10(3):306-311. doi:, 10.1021/acsmedchemlett.8b00508. eCollection 2019 Mar 14. PMID:30891131[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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