Dynamic Behaviors of a<sub>1B</sub>-Adrenergic Receptor in Living Cells

Abstract

AIM: The present study aims at investigating dynamic behaviors of a 1B -adrenergic receptor (a 1B -AR) at molecular level in living cells. METHODS: Wide-field imaging was applied on the detection of real-time dynamic behaviors of a 1B -AR using fluorescence-labeled prazosin (Praz), a specific antagonist of α 1 -AR, in a 1B -AR stably expressed human embryonic kidney 293 (HEK293) living cells. The precise localization around 10 nanometers with 2D Gaussian function was applied in the analysis of the trajectory of molecular movement. RESULTS: The specific binding characteristic of BODIPY-Praz in living cells was identified by the real-time observation that phentolamine competitively inhibits the BODIPY-Praz binding to the receptor at a molecular level in HEK293 living cell. The directional and trapped motions of a 1B -AR molecules in living cells were observed and analyzed at millisecond time resolution and nanometer space resolution. The speeds of the two typical motions were distributed in two different scopes with the peak value of 1.08 and 0.55 μm/s, respectively. The directed motions in living cells were obviously diminished by the previous incubation with the microtubule disrupting agent nocodazole. CONCLUSION: a 1B -AR with binding function was visualized by BODIPY-labeled Praz at molecular level in living cells. The directed and trapped motions have the different speed distributions in living cells. The directed motion of a 1B -AR in living cells might be walking along microtubules.