The non-receptor protein tyrosine phosphatase (PTP) SHP2, encoded by PTPN11, plays an essential role in RAS-mitogen-activated protein kinase (MAPK) signaling during normal development. It has been ...perplexing as to why both enzymatically activating and inactivating mutations in PTPN11 result in human developmental disorders with overlapping clinical manifestations. Here, we uncover a common liquid-liquid phase separation (LLPS) behavior shared by these disease-associated SHP2 mutants. SHP2 LLPS is mediated by the conserved well-folded PTP domain through multivalent electrostatic interactions and regulated by an intrinsic autoinhibitory mechanism through conformational changes. SHP2 allosteric inhibitors can attenuate LLPS of SHP2 mutants, which boosts SHP2 PTP activity. Moreover, disease-associated SHP2 mutants can recruit and activate wild-type (WT) SHP2 in LLPS to promote MAPK activation. These results not only suggest that LLPS serves as a gain-of-function mechanism involved in the pathogenesis of SHP2-associated human diseases but also provide evidence that PTP may be regulated by LLPS that can be therapeutically targeted.
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•Disease-associated mutations endow SHP2 liquid-liquid phase separation capability•SHP2 LLPS is driven by electrostatic interactions mediated by PTP domain•SHP2 allosteric inhibitors block SHP2 LLPS by locking SHP2 in closed conformation•Mutant SHP2 can recruit and activate WT SHP2 in LLPS to promote MAPK activation
Disease-associated mutants of a critical phosphatase in the RAS-MAPK pathway undergo phase separation through a dominant gain-of-function mechanism, explaining how both enzymatically activating and inactivating mutations dysregulate the pathway and can be therapeutically targeted.
Heteroaryldihydropyrimidine (HAP) and sulfamoylbenzamide (SBA) are promising non-nucleos(t)ide HBV replication inhibitors. HAPs are known to promote core protein mis-assembly, but the molecular ...mechanism of abnormal assembly is still elusive. Likewise, the assembly status of core protein induced by SBA remains unknown. Here we show that SBA, unlike HAP, does not promote core protein mis-assembly. Interestingly, two reference compounds HAP_R01 and SBA_R01 bind to the same pocket at the dimer-dimer interface in the crystal structures of core protein Y132A hexamer. The striking difference lies in a unique hydrophobic subpocket that is occupied by the thiazole group of HAP_R01, but is unperturbed by SBA_R01. Photoaffinity labeling confirms the HAP_R01 binding pose at the dimer-dimer interface on capsid and suggests a new mechanism of HAP-induced mis-assembly. Based on the common features in crystal structures we predict that T33 mutations generate similar susceptibility changes to both compounds. In contrast, mutations at positions in close contact with HAP-specific groups (P25A, P25S, or V124F) only reduce susceptibility to HAP_R01, but not to SBA_R01. Thus, HAP and SBA are likely to have distinctive resistance profiles. Notably, P25S and V124F substitutions exist in low-abundance quasispecies in treatment-naïve patients, suggesting potential clinical relevance.
A palladium-catalyzed difluoromethylation of a series of aryl chlorides and triflates under mild conditions was described. A variety of common functional groups were tolerated. In addition, by using ...this protocol, several drug molecules containing an aryl chloride unit were successfully difluoromethylated, thus enabling medicinal chemists to rapidly access novel drug derivatives with potentially improved properties via late-stage functionalization.
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Autoimmune and inflammatory diseases place a huge burden on the healthcare system. Small molecule (SM) therapeutics provide much needed complementary treatment options for these ...diseases. This digest series highlights the latest progress in the discovery and development of safe and efficacious SMs to treat autoimmune and inflammatory diseases with each part representing a class of SMs, namely: 1) protein kinases; 2) nucleic acid-sensing pathways; and 3) soluble ligands and receptors on cell surfaces. In this first part of the series, the focus is on kinase inhibitors that emerged between 2018 and 2020, and which exhibit increased target and tissue selectivity with the aim of increasing their therapeutic index.
The transcriptional enhanced associate domain (TEAD) family of transcription factors serves as the receptors for the downstream effectors of the Hippo pathway, YAP and TAZ, to upregulate the ...expression of multiple genes involved in cellular proliferation and survival. Recent work identified TEAD S-palmitoylation as critical for protein stability and activity as the lipid tail extends into a hydrophobic core of the protein. Here, we report the identification and characterization of a potent small molecule that binds the TEAD lipid pocket (LP) and disrupts TEAD S-palmitoylation. Using a variety of biochemical, structural, and cellular methods, we uncover that TEAD S-palmitoylation functions as a TEAD homeostatic protein level checkpoint and that dysregulation of this lipidation affects TEAD transcriptional activity in a dominant-negative manner. Furthermore, we demonstrate that targeting the TEAD LP is a promising therapeutic strategy for modulating the Hippo pathway, showing tumor stasis in a mouse xenograft model.
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•TEAD palmitoylation serves as a checkpoint to regulate its cellular protein level•Potent compound identified to bind lipid pocket and disrupt homeostasis checkpoint•Compound transforms TEAD into a dominant-negative transcriptional repressor•Dysregulation of TEAD palmitoylation inhibits tumor growth in a xenograft model
Holden et al. identify a potent small molecule that binds the lipid pocket of TEAD transcription factors. Modulation of TEAD palmitoylation disrupts TEAD homeostasis and transforms TEAD into a dominant-negative transcriptional repressor capable of inhibiting tumor growth in a mouse xenograft model.
An efficient chemo- and regioselective N-vinylation of N-heteroarenes has been developed using vinylsulfonium salts. The reaction proceeded under mild and transition-metal-free conditions and ...consistently provided moderate to high yields of vinylation products with 100% E-stereoselectivity. This reaction is also highly chemoselective, and compatible with a variety of functional groups, such as -NHR, -NH2, -OH, -COOH, ester, etc.
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