Colocalization of mineralocorticoid and EGF receptor at the plasma membrane.

The mineralocorticoid receptor (MR), a ligand-activated transcription factor expressed in various cell types (e.g. epithelial cells, neurons, smooth muscle cells, immune cells), plays important roles in neurohumoral, neuronal, cardiovascular, renal and intestinal function. Pathophysiological relevant signaling mechanisms include nongenomic pathways involving the EGF receptor (EGFR). We investigated whether a MR-EGFR colocalization may underlie the functional MR-EGFR interaction by coimmunoprecipitation, fluorescence resonance energy transfer (FRET) and confocal microscopy in a heterologous expression system. EGFR and a small fraction of MR colocalize at the cell membrane, independently of short time exposure (