Bruton’s tyrosine kinase (Btk) is a cytoplasmic protein tyrosine kinase (PTK) crucial for B-cell development and differentiation. It binds to phosphatidylinositol-3,4,5- trísphosphate (PIP3) through the Btk pleckstrin homology (PH) domain. Upon activation, Btk translocates from the cytoplasm to the plasma membrane due to the production of PIP3 by phosphatidylinositol 3-kinase (PI3K) in the membrane. For monitoring the translocation of a Btk-PH-GFP fusion protein from the cytoplasm to the plasma membrane, a high resolution confocal imaging technique and a sophisticated algorithm for quantification of this event is required... View PDF

Transcription factors such as FKHR function as key regulators in e.g. insulin signalling, cell cycle progression and apoptosis downstream of phosphoinositide 3-kinase (PI3K). Inactive FKHR is cytoplasmic but is rapidly imported to the nucleus upon inactivation of the PI3K/Akt pathway. The Forkhead Redistribution^® Assay is designed to assay for inducers of FKHR translocation in FKHR-GFP fusion protein expressing cells. Monitoring the translocation of the fusion protein from the cytosol to the nucleus requires a high resolution imaging technique... View PDF

The beta adrenergic receptor (βAR) is one of the most important targets for the treatment of hypertension and heart failure. Screening for βAR modulators can be achieved using Transfluor^® technology. This assay principle makes use of the recruitment of ß-arrestin molecules to activated receptors and their traffic within the cell and is universally applicable to GPCR activation. Since the readout is a translocation event from a homogeneous distribution of the ß-arrestin molecules within the cytoplasm to clathrin-coated pits and endosomes, it requires a high resolution imaging system with quantitative image analysis capability....View PDF