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Michael
Forster
,
Apirat
Chaikuad
,
Silke m.
Bauer
,
Julia
Holstein
,
Matthew b.
Robers
,
Cesear r.
Corona
,
Matthias
Gehringer
,
Ellen
Pfaffenrot
,
Kamran
Ghoreschi
,
Stefan
Knapp
,
Stefan a.
Laufer
Open Access
Abstract: Janus kinases (JAKs) are a family of cytoplasmatic tyrosine kinases that are attractive targets for the development of anti-inflammatory drugs given their roles in cytokine signaling. One question regarding JAKs and their inhibitors that remains under intensive debate is whether JAK inhibitors should be isoform selective. Since JAK3 functions are restricted to immune cells, an isoform-selective inhibitor for JAK3 could be especially valuable to achieve clinically more useful and precise effects. However, the high degree of structural conservation makes isoform-selective targeting a challenging task. Here, we present picomolar inhibitors with unprecedented kinome-wide selectivity for JAK3. Selectivity was achieved by concurrent covalent reversible targeting of a JAK3-specific cysteine residue and a ligand-induced binding pocket. We confirmed that in vitro activity and selectivity translate well into the cellular environment and suggest that our inhibitors are powerful tools to elucidate JAK3-specific functions.
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Nov 2016
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Jennifer
Batson
,
Hamish D.
Toop
,
Clara
Redondo
,
Roya
Babaebi-jadidi
,
Apirat
Chaikuad
,
Stephen F.
Wearmouth
,
Brian
Gibbons
,
Claire
Allen
,
Cynthia
Tallant
,
Jingxue
Zhang
,
Chunyun
Du
,
Jules
Hancox
,
Tom
Hawtrey
,
Joana
Da Rocha
,
Renate
Griffith
,
Stefan
Knapp
,
David O.
Bates
,
Jonathan C.
Morris
Open Access
Abstract: Serine/arginine-protein kinase 1 (SRPK1) regulates alternative splicing of VEGF-A to pro-angiogenic isoforms and SRPK1 inhibition can restore the balance of pro/antiangiogenic isoforms to normal physiological levels. The lack of potency and selectivity of available compounds has limited development of SRPK1 inhibitors, with the control of alternative splicing by splicing factor-specific kinases yet to be translated. We present here compounds that occupy a binding pocket created by the unique helical insert of SRPK1, and trigger a backbone flip in the hinge region, that results in potent (<10 nM) and selective inhibition of SRPK1 kinase activity. Treatment with these inhibitors inhibited SRPK1 activity and phosphorylation of serine/arginine splicing factor 1 (SRSF1), resulting in alternative splicing of VEGF-A from pro-angiogenic to antiangiogenic isoforms. This property resulted in potent inhibition of blood vessel growth in models of choroidal angiogenesis in vivo. This work identifies tool compounds for splice isoform selective targeting of pro-angiogenic VEGF, which may lead to new therapeutic strategies for a diversity of diseases where dysfunctional splicing drives disease development.
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Feb 2017
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Moses
Moustakim
,
Thomas
Christott
,
Octovia P.
Monteiro
,
James
Bennett
,
Charline
Giroud
,
Jennifer
Ward
,
Catherine M.
Rogers
,
Paul
Smith
,
Ioanna
Panagakou
,
Laura
Diaz-saez
,
Suet Ling
Felce
,
Vicki
Gamble
,
Carina
Gileadi
,
Nadia
Halidi
,
David
Heidenreich
,
Apirat
Chaikuad
,
Stefan
Knapp
,
Kilian V. M.
Huber
,
Gillian
Farnie
,
Jag
Heer
,
Nenad
Manevski
,
Gennady
Poda
,
Rima
Al-awar
,
Darren J.
Dixon
,
Paul E.
Brennan
,
Oleg
Fedorov
Abstract: YEATS domain (YD) containing proteins are an emerging class of epigenetic targets in drug discovery. Dysregulation of these modified lysine‐binding proteins has been linked to the onset and progression of cancers. We herein report the discovery and characterisation of the first small‐molecule chemical probe, SGC‐iMLLT, for the YD of MLLT1 (ENL/YEATS1) and MLLT3 (AF9/YEATS3). SGC‐iMLLT is a potent and selective inhibitor of MLLT1/3–histone interactions. Excellent selectivity over other human YD proteins (YEATS2/4) and bromodomains was observed. Furthermore, our probe displays cellular target engagement of MLLT1 and MLLT3. The first small‐molecule X‐ray co‐crystal structures with the MLLT1 YD are also reported. This first‐in‐class probe molecule can be used to understand MLLT1/3‐associated biology and the therapeutic potential of small‐molecule YD inhibitors.
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Oct 2018
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Open Access
Abstract: Bone morphogenetic proteins (BMPs) are secreted ligands of the transforming growth factor-β (TGF-β) family that control embryonic patterning, as well as tissue development and homeostasis. Loss of function mutations in the type II BMP receptor BMPR2 are the leading cause of pulmonary arterial hypertension (PAH), a rare disease of vascular occlusion that leads to high blood pressure in the pulmonary arteries. To understand the structural consequences of these mutations, we determined the crystal structure of the human wild-type BMPR2 kinase domain at 2.35 Å resolution. The structure revealed an active conformation of the catalytic domain that formed canonical interactions with the bound ligand Mg-ADP. Disease-associated missense mutations were mapped throughout the protein structure, but clustered predominantly in the larger kinase C-lobe. Modelling revealed that the mutations will destabilize the protein structure by varying extents consistent with their previously reported functional heterogeneity. The most severe mutations introduced steric clashes in the hydrophobic protein core, whereas those found on the protein surface were less destabilizing and potentially most favorable for therapeutic rescue strategies currently under clinical investigation.
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Dec 2019
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I02-Macromolecular Crystallography
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Open Access
Abstract: Bone morphogenetic protein (BMP) receptor kinases are tightly regulated to control development and tissue homeostasis. Mutant receptor kinase domains escape regulation leading to severely degenerative diseases and represent an important therapeutic target. Fibrodysplasia ossificans progressiva (FOP) is a rare but devastating disorder of extraskeletal bone formation. FOP-associated mutations in the BMP receptor ALK2 reduce binding of the inhibitor FKBP12 and promote leaky signaling in the absence of ligand. To establish structural mechanisms of receptor regulation and to address the effects of FOP mutation, we determined the crystal structure of the cytoplasmic domain of ALK2 in complex with the inhibitors FKBP12 and dorsomorphin. FOP mutations break critical interactions that stabilize the inactive state of the kinase, thereby facilitating structural rearrangements that diminish FKBP12 binding and promote the correct positioning of the glycine-serine-rich loop and ?C helix for kinase activation. The balance of these effects accounts for the comparable activity of R206H and L196P. Kinase activation in the clinically benign mutant L196P is far weaker than R206H but yields equivalent signals due to the stronger interaction of FKBP12 with R206H. The presented ALK2 structure offers a valuable template for the further design of specific inhibitors of BMP signaling.
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Oct 2012
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I02-Macromolecular Crystallography
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Jan S.
Kramer
,
Stefano
Woltersdorf
,
Thomas
Duflot
,
Kerstin
Hiesinger
,
Felix F.
Lillich
,
Felix
Knöll
,
Sandra K.
Wittmann
,
Franca M.
Klingler
,
Steffen
Brunst
,
Apirat
Chaikuad
,
Christophe
Morisseau
,
Bruce D.
Hammock
,
Carola
Buccellati
,
Angelo
Sala
,
G. Enrico
Rovati
,
Matthieu
Leuillier
,
Sylvain
Fraineau
,
Julie
Rondeaux
,
Victor
Hernandez Olmos
,
Jan
Heering
,
Daniel
Merk
,
Denys
Pogoryelov
,
Dieter
Steinhilber
,
Stefan
Knapp
,
Jeremy
Bellien
,
Ewgenij
Proschak
Abstract: The emerging pharmacological target soluble epoxide hydrolase (sEH) is a bifunctional enzyme exhibiting two different catalytic activities, which are located in two distinct domains. Although the physiological role of the C-terminal hydrolase domain is well-investigated, little is known about its phosphatase activity located in the N-terminal domain of the sEH (sEH-P). Herein, we report the discovery and optimization of the first inhibitor of human and rat sEH-P, applicable in vivo. X-ray structure analysis of the sEH phosphatase domain complexed with an inhibitor provides insights in the molecular basis of small-molecule sEH-P inhibition and helps to rationalize the structure-activity relationships. 4-(4-(3,4-Dichlorophenyl)-5-phenyloxazol-2-yl)butanoic acid (22b, SWE101) has an excellent pharmacokinetic and pharmacodynamic profile in rats and enables the investigation of the physiological and pathophysiological role of sEH-P in vivo.
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Aug 2019
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I02-Macromolecular Crystallography
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Alfredo
Picado
,
Apirat
Chaikuad
,
Carrow I.
Wells
,
Safal
Shrestha
,
William J.
Zuercher
,
Julie E.
Pickett
,
Frank E.
Kwarcinski
,
Parvathi
Sinha
,
Chandi S.
De Silva
,
Reena
Zutshi
,
Shubin
Liu
,
Natarajan
Kannan
,
Stefan
Knapp
,
David H.
Drewry
,
Timothy M.
Willson
Diamond Proposal Number(s):
[442]
Abstract: STK17B is a member of the death-associated protein kinase family and has been genetically linked to the development of diverse diseases. However, the role of STK17B in normal and disease pathology is poorly defined. Here, we present the discovery of thieno[3,2-d] pyrimidine SGC-STK17B-1 (11s), a high-quality chemical probe for this understudied “dark” kinase. 11s is an ATP-competitive inhibitor that showed remarkable selectivity over other kinases including the closely related STK17A. X-ray crystallography of 11s and related thieno[3,2-d]pyrimidines bound to STK17B revealed a unique P-loop conformation characterized by a salt bridge between R41 and the carboxylic acid of the inhibitor. Molecular dynamic simulations of STK17B revealed the flexibility of the P-loop and a wide range of R41 conformations available to the apo-protein. The isomeric thieno[2,3-d]pyrimidine SGC-STK17B-1N (19g) was identified as a negative control compound. The >100-fold lower activity of 19g on STK17B was attributed to the reduced basicity of its pyrimidine N1.
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Nov 2020
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I02-Macromolecular Crystallography
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Diamond Proposal Number(s):
[442]
Abstract: Selectivity remains a challenge for ATP-mimetic kinase inhibitors, an issue that may be overcome by targeting unique residues or binding pockets. However, to date only few strategies have been developed. Here we identify that bulky residues located N-terminal to the DFG motif (DFG-1) represent an opportunity for designing highly selective inhibitors with unexpected binding modes. We demonstrate that several diverse inhibitors exerted selective, non-canonical binding modes that exclusively target large hydrophobic DFG-1 residues present in many kinases including PIM, CK1, DAPK and CLK. Using the CLK family as a model, structural and biochemical data revealed that the DFG-1 valine controlled a non-canonical binding mode in CLK1, providing a rational for selectivity over the closely-related CLK3 which harbors a smaller DFG-1 alanine. Our data suggests that targeting the restricted back pocket in the small fraction of kinases that harbor bulky DFG-1 residues offers a versatile selectivity filter for inhibitor design.
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Aug 2020
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I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
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Abstract: Glycogenin initiates the synthesis of a maltosaccharide chain covalently attached to itself on Tyr195 via a stepwise glucosylation reaction, priming glycogen synthesis. We have captured crystallographic snapshots of human glycogenin during its reaction cycle, revealing a dynamic conformational switch between ground and active states mediated by the sugar donor UDP-glucose. This switch includes the ordering of a polypeptide stretch containing Tyr195, and major movement of an approximately 30-residue “lid” segment covering the active site. The rearranged lid guides the nascent maltosaccharide chain into the active site in either an intra- or intersubunit mode dependent upon chain length and steric factors and positions the donor and acceptor sugar groups for catalysis. The Thr83Met mutation, which causes glycogen storage disease XV, is conformationally locked in the ground state and catalytically inactive. Our data highlight the conformational plasticity of glycogenin and coexistence of two modes of glucosylation as integral to its catalytic mechanism.
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Dec 2011
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I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
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Peter
Canning
,
Christopher D. O.
Cooper
,
Tobias
Krojer
,
James W.
Murray
,
Ashley C. W.
Pike
,
Apirat
Chaikuad
,
Tracy
Keates
,
Chancievan
Thangaratnarajah
,
Viktorija
Hojzan
,
Brian D.
Marsden
,
Opher
Gileadi
,
Stefan
Knapp
,
Frank
Von Delft
,
Alex N.
Bullock
Open Access
Abstract: Cullin-RING ligases are multisubunit E3 ubiquitin ligases that recruit substrate-specific adaptors to catalyze protein ubiquitylation. Cul3-based Cullin-RING ligases are uniquely associated with BTB adaptors that incorporate homodimerization, Cul3 assembly, and substrate recognition into a single multidomain protein, of which the best known are BTB-BACK-Kelch domain proteins, including KEAP1. Cul3 assembly requires a BTB protein “3-box” motif, analogous to the F-box and SOCS box motifs of other Cullin-based E3s. To define the molecular basis for this assembly and the overall architecture of the E3, we determined the crystal structures of the BTB-BACK domains of KLHL11 both alone and in complex with Cul3, along with the Kelch domain structures of KLHL2 (Mayven), KLHL7, KLHL12, and KBTBD5. We show that Cul3 interaction is dependent on a unique N-terminal extension sequence that packs against the 3-box in a hydrophobic groove centrally located between the BTB and BACK domains. Deletion of this N-terminal region results in a 30-fold loss in affinity. The presented data offer a model for the quaternary assembly of this E3 class that supports the bivalent capture of Nrf2 and reveals potential new sites for E3 inhibitor design.
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Jan 2013
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