Chemical inducers of dimerization

Fig. 7.12. Structures of several of the small molecules used as Chemical Inducers of Dimerizations (CIDs) in the three-hybrid systems to date.

Signal transduction pathways can also be elucidated by incorporating variant proteins, which require chemical inducers of dimerization to function. These small molecules can cause two proteins to come together to initiate the signal. 

Chemical inducers of dimerization (CID) are bivalent small molecules that bind t vo proteins simultaneously. The purpose of these molecules is to bring the proteins together to induce signal transduction [27]. For brevity, we will limit our discussion to CIDs that directly control transcription. The basic architecture of these systems consists of two chimeric proteins. The first contains a DNA-binding domain (DBD) fused to a ligand-binding domain (LBD) and the second chimera contains an LBD and an activation domain (AD). The small molecule that binds both of these proteins simultaneously induces proximity of the two proteins, resulting in transcription activation (Fig. 8.11). 

Fig.8.n Chemical inducers of dimerization (CID) to control transcription. This system requires two chimeric proteins, one comprising a DNA-binding domain (DBD) fused to a ligand-binding domain (LBD), and the other comprising an LBD fused to a transcriptional... 

Rg. 8.12 Orthogonal chemical inducers of dimerization. AP21967 is a rapamycin analogue that binds both FKBP and the T2098L variant... 

Chemical Inducers of Dimerization to Control Transcription 200 OLRPs and ATP Analogues 202 Summary 204 References 206... 

Examples of small molecules, altered cell culture conditions, proteins, and genetic constructs used to probe RME. CID chemical inducer of dimerization. 

Belshaw PJ, Spencer DM, Crabtree GR, Schreiber SL. Controlling programmed cell death with a cyclophilin-cyclosporin-based chemical inducer of dimerization. Chem. Biol. 1996 3 731-738. Mallet VO, Mitchell C, Guidotti JE, Jaffray P, Fabre M, Spencer D, Amoult D, Kahn A, Gilgenkrantz H. Conditional cell ablation by tight control of caspase-3 dimerization in transgenic mice. Nat. Biotechnol 2002 20 1234-1239. 

Stankunas K, Bayle JH, Gestwicki JE, Lin YM, Wandless TJ, Crabtree GR. Conditional protein alleles using knockin mice and a chemical inducer of dimerization. Mol. Cell 2003 12 1615-1624. 

Just as a dimeric RNA molecule can be introduced to mediate the interaction between the DNA-binding and ADs, so can a dimeric small molecule [17]. In fact, well before their use in a small molecule three-hybrid assay, dimeric small molecules were used as chemical inducers of dimerization (CIDs) to artificially oligomerize fusion proteins in vivo [18]. In the yeast three-hybrid system, the union of two protein fusions and a CID reconstitute the transcription of a reporter gene (Fig. 4.1-3(d)). In 1996, Licitra and Liu built what they called a yeast three-hybrid assay [19]. This assay consists of two fusion proteins and a heterodimeric small molecule CID that brings these fusion proteins together to activate the transcription of a reporter gene (Fig. 4.1-3 d)). 

Fig. 4.1-5 Small molecules used to create chemical inducers of dimerization (Cl Ds) for the yeast three-hybrid system.

G.R. Crabtree, Conditional protein alleles using Knockin mice and a chemical inducer of dimerization,... 

Activation of c-Abl kinase activity and transformation by a chemical inducer of dimerization, J. Biol. Chem. 2001, 276, 24372-24379. 

The labeling of AGT fusion proteins is not restricted to monitor protein function, but can be also used to manipulate it. One example for this approach is induced protein dimerization through covalent labeling of AGT fusion proteins [43]. The dynamic dimerization and dissociation of pairs of proteins plays an important role in various biological processes. As a chemical approach to study processes that depend on protein dimerization, the teams of Schreiber, Crabtree have introduced chemical inducers of dimerization (Cl Ds) [44]. ClDs are cell-permeable molecules, which can bind simultaneously to two different proteins, thereby inducing their dimerization. Various biological processes have... 

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