TAG Degradation Platform

The TAG Degradation Platform enables the knockdown of your protein of interest (POI) by adding a tag (or degron tag), via genetic modification, which can then be targeted by a small molecule Degrader.

The dTAG technique involves the expression of a protein of interest as a fusion with mutant FKBP12^F36V via transgene expression or CRISPR-mediated locus-specific knock-in. dTAG Degraders are heterobifunctional, comprising a synthetic ligand (AP1836), that selectively binds FKBP12^F36V linked to an E3 ligase ligand, such as Thalidomide. The dTAG Degrader recruits the fusion protein to the E3 ligase complex, bringing about its ubiquitination and subsequent degradation by the proteasome.

In the aTAG (Achilles TAG) system, the protein of interest is expressed as a fusion with the enzyme MTH1 (MutT homolog-1; NUDT1). MTH1 is used as the TAG since there is no known phenotypic consequence resulting from the loss of this protein. The aTAG Degrader comprises a ligand selective for MTH1 linked to an E3 ligase ligand. As with dTAG, aTAG Degraders provide potent and rapid degradation of the fusion protein, and have a range of properties suitable for in vitro and in vivo applications. For more information on the CRIPSR-mediated knock-in of MTH1 fusion proteins, see accompanying Protocol.

The BromoTag platform uses Brd4^{BD2 L387A}, a variant of the BET bromodomain BRD4, as the tag fused to the target POI. The BromoTag Degrader comprises a VHL E3 ligase ligand joined by a linker to a (+)-JQ1 (Cat. No. 4499) derivative that selectively binds the Brd4^{BD2 L387A} variant.

TAG Technology for Target Validation

Figure 1: Schematic showing the mode of action of TAG Degraders. A protein of interest is expressed as a fusion with a "TAG" protein. For the dTAG system the protein of interest is tagged with F36V single-point mutated FKBP12; the aTAG system uses MTH1 as the TAG; and in the BromoTag system the POI is tagged with a BRD4^{BD2 L387A} variant. The dTAG/aTAG Degrader initiates the formation of a ternary complex between an E3 ubiquitin ligase and the fusion protein which results in polyubiquitination of the target protein, its recognition by the proteasome and subsequent degradation of the entire protein. dTAG/aTAG molecules act catalytically, repeatedly engaging and directing the ubiquitination of target molecules.

Custom knock-in cell lines for the dTAG and aTAG platforms are available from Bio-Techne. Visit bio-techne.com to find out more.

Plasmid vectors for the lentiviral expression and CRISPR-mediated knock-in of FKBP12^F36V are available from Addgene.

BromoTag^® is a registered trademark of the University of Dundee and is used under license.

Literature for TAG Degradation Platform

Tocris offers the following scientific literature for TAG Degradation Platform to showcase our products. We invite you to request* your copy today!

*Please note that Tocris will only send literature to established scientific business / institute addresses.

Targeted Protein Degradation Research Product Guide

This brochure highlights the tools and services available from Bio-Techne to support Targeted Protein Degradation research, including:

• Active Degraders
• TAG Degradation Platform
• Degrader Building Blocks
• Ubiquitin-Proteasome System Proteins
• Assays for Protein Degradation

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Targeted Protein Degradation Poster

Degraders (e.g. PROTACs) are bifunctional small molecules, that harness the Ubiquitin Proteasome System (UPS) to selectively degrade target proteins within cells. They consist of three covalently linked components: an E3 ubiquitin ligase ligand, a linker and a ligand for the target protein of interest. Authored in-house, this poster outlines the generation of a toolbox of building blocks for the development of Degraders. The characteristics and selection of each of these components are discussed. Presented at EFMC 2018, Ljubljana, Slovenia

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Validating Targets for TPD Using dTAG Poster

The dTAG platform offers a generalizable strategy to degrade, in principle, any intracellular protein of interest (POI) and is a useful strategy for exploration and validation of targets. This poster presents a workflow solution for target validation, from custom TAG knock-in cell-lines for your POI, different dTAG Degraders to knockdown you POI, to automated assays for protein degradation using Simple Western^TM instruments. Data are also presented on the use of an antibody that recognizes the TAG domain (FKBP12^F36V) for detection of degradation. Presented at TPD Europe, March 2022, London, UK.

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