Related Experiment Videos
Design and application of a cytokine-receptor-based interaction trap
S Eyckerman1, A Verhee, J V der Heyden
1Flanders Interuniversity Institute for Biotechnology, VIB09, Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Ghent University, K.L. Ledeganckstraat 35, B-9000 Ghent, Belgium.
Abstract:
Ligand-induced clustering of type I cytokine receptor subunits leads to trans-phosphorylation and activation of associated cytosolic janus kinases (JAKs). In turn, JAKs phosphorylate tyrosine residues in the receptor tails, leading to recruitment and activation of signalling molecules. Among these, signal transducers and activators of transcription (STATs) are important in the direct transmission of signals to the nucleus. Here, we show that incorporation of an interaction trap in a signalling-deficient receptor allows the identification of protein-protein interactions, using a STAT-dependent complementation assay. Mammalian protein-protein interaction trap (MAPPIT) adds to existing yeast two-hybrid procedures, as originally explored by Fields and Song, and permits the detection of both modification-independent and of phosphorylation-dependent interactions in intact human cells. We also demonstrate that MAPPIT can be used to screen complex complementary DNA libraries, and using this approach, we identify cytokine-inducible SH2-containing protein (CIS) and suppressor of cytokine signalling-2 (SOCS-2) as interaction partners of the phosphotyrosine 402 (Tyr 402)-binding motif in the erythropoietin receptor (EpoR). Importantly, this approach places protein-protein interactions in their normal physiological context, and is especially applicable to the in situ analysis of signal transduction pathways.
Insights
Researchers developed a new method, Mammalian Protein-Protein Interaction Trap (MAPPIT), to identify protein interactions in human cells. This technique successfully identified new partners for the erythropoietin receptor, advancing our understanding of cell signaling pathways.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- Type I cytokine receptors initiate signaling cascades upon ligand binding, involving janus kinases (JAKs) and signal transducers and activators of transcription (STATs).
- Understanding protein-protein interactions within these pathways is crucial for deciphering signal transduction mechanisms.
Purpose of the Study:
- To develop and validate a novel mammalian protein-protein interaction trap (MAPPIT) assay for identifying interactions in intact human cells.
- To demonstrate MAPPIT's utility in screening complementary DNA libraries and identifying novel interaction partners.
Main Methods:
- Development of the Mammalian Protein-Protein Interaction Trap (MAPPIT) assay utilizing a signaling-deficient receptor and a STAT-dependent complementation system.
- Application of MAPPIT to screen complementary DNA libraries.
- Validation of identified interactions using the erythropoietin receptor (EpoR) phosphotyrosine 402 (Tyr 402)-binding motif.
Main Results:
- MAPPIT successfully detects both modification-independent and phosphorylation-dependent protein-protein interactions in live human cells.
- The assay identified cytokine-inducible SH2-containing protein (CIS) and suppressor of cytokine signalling-2 (SOCS-2) as novel interaction partners of the EpoR Tyr 402 motif.
- MAPPIT provides a physiologically relevant context for studying protein interactions.
Conclusions:
- MAPPIT is a powerful and versatile tool for identifying protein-protein interactions in their native cellular environment.
- This method enhances existing techniques like yeast two-hybrid assays by enabling analysis within intact human cells.
- MAPPIT facilitates the in situ analysis of signal transduction pathways and the discovery of novel signaling components.