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Tracking the A2A adenosine receptor

Background

The A2A adenosine receptor has become a drug target in the treatment of Parkinson’s disease, psychotic behavior and dementia. In addition, targeted deletion of this receptor in mice leads to hypertension, increased platelet aggregation, male aggressiveness and decreased susceptibility to ischemic brain damage. The potential clinical relevance of this receptor is obvious. The A2A adenosine receptor, a prototypical GPCR, is known to signal via restricted collision coupling with Gs. In addition, it is able to stimulate MAP kinase/ERK in a Gs-independent way but dependent on the lipid microenvironment of the membrane. Hence, we characterized the mobility and the targeting of the A2A receptor in nerve cells.

Methods

Receptor mobility was measured using fluorescence recovery after photobleaching (FRAP). A fluorophore-tagged version of the A2A receptor expressed in the cell membrane was bleached using an intense laser beam and the lateral diffusion rate of the receptor was determined. We also implemented the method of single molecule tracking, which allows for the observation of movements of single receptors in real spatial and temporal resolution.

Results

We introduced a palmitoylation site in the proximal part of the C-terminus of the A2A receptor; this led to the loss of restricted collision coupling of the receptor to its G protein. We also deleted a DVELL motif in the distal part of the C-terminus, which disrupted the interaction of the receptor with a “synaptic associated protein” (SAP102). The mobility of these mutants has been compared with wild-type A2A receptors in different compartments of hippocampal neurons.

Conclusions

The signaling properties of the A2A adenosine receptor depend on its localization within several membrane compartments. Targeting to specific compartments depends on the interaction with “accessory proteins”.

Author information

Correspondence to Jürgen Zezula.

Rights and permissions

Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Keywords

  • Intense Laser
  • Fluorescence Recovery After Photobleaching
  • Fluorescence Recovery
  • Ischemic Brain Damage
  • Membrane Compartment