Fluorescence Resonance Energy Transfer Reveals that Serca Dimerizes and Forms a Complex with Phospholamban in a 2:1 Stoichiometry

Abstract

The sarco/endoplasmic reticulum calcium ATPase (SERCA) has been proposed to form functional dimers in vitro. In order to investigate whether SERCA forms homo-dimers in live cells, we fused canine SERCA2a to cerulean (Cer) or yellow fluorescent protein (YFP), and quantified SERCA-SERCA interactions by fluorescence resonance energy transfer (FRET). SERCA-SERCA FRET efficiency was dependent on the labeling position of the fluorescent protein tags, with the highest FRET efficiency achieved when the respective fluorescent proteins were fused to SERCA N-termini.