RESUMO
Hedgehog signaling is critical for correct embryogenesis and tissue development. However, on maturation, signaling is also found to be aberrantly activated in many cancers. Palmitoylation of the secreted signaling protein sonic hedgehog (Shh) by the enzyme hedgehog acyltransferase (Hhat) is required for functional signaling. To quantify this important posttranslational modification, many in vitro Shh palmitoylation assays employ radiolabeled fatty acids, which have limitations in terms of cost and safety. Here we present a click chemistry armed enzyme-linked immunosorbent assay (click-ELISA) for assessment of Hhat activity through acylation of biotinylated Shh peptide with an alkyne-tagged palmitoyl-CoA (coenzyme A) analogue. Click chemistry functionalization of the alkyne tag with azido-FLAG peptide allows analysis through an ELISA protocol and colorimetric readout. This assay format identified the detergent n-dodecyl ß-d-maltopyranoside as an improved solubilizing agent for Hhat activity. Quantification of the potency of RU-SKI small molecule Hhat inhibitors by click-ELISA indicated IC50 values in the low- or sub-micromolar range. A stopped assay format was also employed that allows measurement of Hhat kinetic parameters where saturating substrate concentrations exceed the binding capacity of the streptavidin-coated plate. Therefore, click-ELISA represents a nonradioactive method for assessing protein palmitoylation in vitro that is readily expandable to other classes of protein lipidation.
Assuntos
Aciltransferases/metabolismo , Proteínas Hedgehog/metabolismo , Processamento de Proteína Pós-Traducional , Aciltransferases/antagonistas & inibidores , Aciltransferases/química , Aciltransferases/genética , Biotinilação , Química Click , Detergentes/química , Inibidores Enzimáticos/farmacologia , Ensaio de Imunoadsorção Enzimática , Ácidos Graxos Insaturados/farmacologia , Células HEK293 , Proteínas Hedgehog/química , Humanos , Proteínas Imobilizadas/química , Proteínas Imobilizadas/metabolismo , Lipoilação/efeitos dos fármacos , Maltose/análogos & derivados , Maltose/química , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Palmitoil Coenzima A/análogos & derivados , Palmitoil Coenzima A/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Solubilidade , Estreptavidina/química , Estreptavidina/metabolismo , Especificidade por SubstratoRESUMO
In this data article we describe synthetic and characterisation data for four members of the 5-acyl-6,7-dihydrothieno[3,2-c]pyridine (termed "RU-SKI") class of inhibitors of Hedgehog acyltransferase, including associated NMR spectra for final compounds. RU-SKI compounds were selected for synthesis based on their published high potencies against the enzyme target. RU-SKI 41 (9a), RU-SKI 43 (9b), RU-SKI 101 (9c), and RU-SKI 201 (9d) were profiled for activity in the related article "Click chemistry armed enzyme linked immunosorbent assay to measure palmitoylation by Hedgehog acyltransferase" (Lanyon-Hogg et al., 2015) [1]. (1)H NMR spectral data indicate different amide conformational ratios between the RU-SKI inhibitors, as has been observed in other 5-acyl-6,7-dihydrothieno[3,2-c]pyridines. The synthetic and characterisation data supplied in the current article provide validated access to the class of RU-SKI inhibitors.