View source for 4rx5


==Bruton's tyrosine kinase (BTK) with pyridazinone compound 23==
<StructureSection load='4rx5' size='340' side='right'caption='[[4rx5]], [[Resolution|resolution]] 1.36&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4rx5]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4RX5 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4RX5 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.356&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=3YO:N-(6-FLUORO-2-METHYL-3-{5-[(5-METHYL-4,5,6,7-TETRAHYDROPYRAZOLO[1,5-A]PYRAZIN-2-YL)AMINO]-6-OXO-1,6-DIHYDROPYRIDAZIN-3-YL}PHENYL)-1-BENZOTHIOPHENE-2-CARBOXAMIDE'>3YO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PG0:2-(2-METHOXYETHOXY)ETHANOL'>PG0</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4rx5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4rx5 OCA], [https://pdbe.org/4rx5 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4rx5 RCSB], [https://www.ebi.ac.uk/pdbsum/4rx5 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4rx5 ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/BTK_HUMAN BTK_HUMAN] Defects in BTK are the cause of X-linked agammaglobulinemia (XLA) [MIM:[https://omim.org/entry/300755 300755]; also known as X-linked agammaglobulinemia type 1 (AGMX1) or immunodeficiency type 1 (IMD1). XLA is a humoral immunodeficiency disease which results in developmental defects in the maturation pathway of B-cells. Affected boys have normal levels of pre-B-cells in their bone marrow but virtually no circulating mature B-lymphocytes. This results in a lack of immunoglobulins of all classes and leads to recurrent bacterial infections like otitis, conjunctivitis, dermatitis, sinusitis in the first few years of life, or even some patients present overwhelming sepsis or meningitis, resulting in death in a few hours. Treatment in most cases is by infusion of intravenous immunoglobulin.<ref>PMID:7880320</ref> <ref>PMID:8013627</ref> <ref>PMID:8162056</ref> <ref>PMID:8162018</ref> <ref>PMID:7849697</ref> <ref>PMID:7849721</ref> <ref>PMID:7809124</ref> <ref>PMID:7849006</ref> <ref>PMID:7711734</ref> <ref>PMID:7633420</ref> <ref>PMID:7633429</ref> <ref>PMID:8634718</ref> <ref>PMID:7627183</ref> <ref>PMID:7897635</ref> <ref>PMID:8723128</ref> <ref>PMID:8695804</ref> <ref>PMID:8834236</ref> <ref>PMID:9280283</ref> <ref>PMID:9260159</ref> <ref>PMID:9545398</ref> <ref>PMID:9445504</ref> <ref>PMID:10220140</ref> <ref>PMID:10678660</ref> <ref>PMID:10612838</ref>   Defects in BTK may be the cause of X-linked hypogammaglobulinemia and isolated growth hormone deficiency (XLA-IGHD) [MIM:[https://omim.org/entry/307200 307200]; also known as agammaglobulinemia and isolated growth hormone deficiency or Fleisher syndrome or isolated growth hormone deficiency type 3 (IGHD3). In rare cases XLA is inherited together with isolated growth hormone deficiency (IGHD).
== Function ==
[https://www.uniprot.org/uniprot/BTK_HUMAN BTK_HUMAN] Non-receptor tyrosine kinase indispensable for B lymphocyte development, differentiation and signaling. Binding of antigen to the B-cell antigen receptor (BCR) triggers signaling that ultimately leads to B-cell activation. After BCR engagement and activation at the plasma membrane, phosphorylates PLCG2 at several sites, igniting the downstream signaling pathway through calcium mobilization, followed by activation of the protein kinase C (PKC) family members. PLCG2 phosphorylation is performed in close cooperation with the adapter protein B-cell linker protein BLNK. BTK acts as a platform to bring together a diverse array of signaling proteins and is implicated in cytokine receptor signaling pathways. Plays an important role in the function of immune cells of innate as well as adaptive immunity, as a component of the Toll-like receptors (TLR) pathway. The TLR pathway acts as a primary surveillance system for the detection of pathogens and are crucial to the activation of host defense. Especially, is a critical molecule in regulating TLR9 activation in splenic B-cells. Within the TLR pathway, induces tyrosine phosphorylation of TIRAP which leads to TIRAP degradation. BTK plays also a critical role in transcription regulation. Induces the activity of NF-kappa-B, which is involved in regulating the expression of hundreds of genes. BTK is involved on the signaling pathway linking TLR8 and TLR9 to NF-kappa-B. Transiently phosphorylates transcription factor GTF2I on tyrosine residues in response to BCR. GTF2I then translocates to the nucleus to bind regulatory enhancer elements to modulate gene expression. ARID3A and NFAT are other transcriptional target of BTK. BTK is required for the formation of functional ARID3A DNA-binding complexes. There is however no evidence that BTK itself binds directly to DNA. BTK has a dual role in the regulation of apoptosis.<ref>PMID:9012831</ref> <ref>PMID:11606584</ref> <ref>PMID:16517732</ref> <ref>PMID:16738337</ref> <ref>PMID:16415872</ref> <ref>PMID:17932028</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
BTK inhibitor GDC-0834 (1) was found to be rapidly metabolized in human studies, resulting in a suspension of clinical trials. The primary route of metabolism was through cleavage of the acyclic amide bond connecting the terminal tetrahydrobenzothiophene with the central linker aryl ring. SAR studies were focused on reducing metabolic cleavage of this amide, and resulted in the identification of several central aryl linker substituents that conferred improved stability. The most promising substituted aryl linkers were then incorporated into an optimized pyridazinone scaffold, resulting in the identification of lead analog 23, possessing improved potency, metabolic stability and preclinical properties.

Discovery of highly potent and selective Bruton's tyrosine kinase inhibitors: Pyridazinone analogs with improved metabolic stability.,Young WB, Barbosa J, Blomgren P, Bremer MC, Crawford JJ, Dambach D, Eigenbrot C, Gallion S, Johnson AR, Kropf JE, Lee SH, Liu L, Lubach JW, Macaluso J, Maciejewski P, Mitchell SA, Ortwine DF, Di Paolo J, Reif K, Scheerens H, Schmitt A, Wang X, Wong H, Xiong JM, Xu J, Yu C, Zhao Z, Currie KS Bioorg Med Chem Lett. 2016 Jan 15;26(2):575-9. doi: 10.1016/j.bmcl.2015.11.076., Epub 2015 Nov 24. PMID:26675441<ref>PMID:26675441</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4rx5" style="background-color:#fffaf0;"></div>

==See Also==
*[[Tyrosine kinase 3D structures|Tyrosine kinase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Eigenbrot C]]
[[Category: Yu C]]