Tandem Ubiquitin Binding Entities (TUBEs) are poly-ubiquitin capture reagents that consist of polymerized ubiquitin associated domains (UBDs). TUBEs bind to poly-ubiquitin chains with a high affinity (low nanomolar range). TUBEs are divided into 2 categories: pan-selective and chain-selective. Pan Selective TUBEs bind to all types of poly-ubiquitin linkages; whereas chain-selective TUBEs only bind to a specific type of poly-ubiquitin linkage.

As TUBEs can be conjugated to different moieties, they can be used for different research purposes. Bead-conjugated and affinity tagged TUBEs are used for purification and enrichment of poly-ubiquitinated proteins. HRP/Biotin-conjugated TUBEs are used for detection of poly-ubiquitinated proteins in Western blots; whereas fluorescence-tagged TUBEs are used for imaging purposes. In addition to that, TUBEs are incorporated in the different in vitro and cell-based assays/kits developed and commercialized by LifeSensors.