Identification and verification of proteins interacting with the Kappa Opioid Receptor (KOPR)

Abstract

Proteins that interact with the human kappa opioid receptor (hKOPR) may contribute to regulation and signaling of the receptor. In this paper, we focus on the protein 14-3-3zeta that regulates anterograde transport of the hKOPR from the endoplasmic reticulum (ER) to the Golgi apparatus. 14-3-3zeta interacts with the C-terminal domain of the receptor and promotes cell surface expression of the hKOPR by inhibiting coatomer protein I (COPI) and RVR motif-mediated ER retension of the hKOPR. Here we describe three experimental procedures we used to evaluate the interaction between hKOPR and 14-3-3zeta: co-immunoprecipitation, pull-down assay and immunofluorescence microscopy.