Structure and function of adenosine receptor heteromers.

Area of Science:

• Biochemistry and Molecular Biology
• Pharmacology
• Cell Signaling

Background:

• Adenosine is a fundamental signaling molecule with conserved receptors across species.
• Mammalian cells express four adenosine receptors (A₁, A_2A, A_2B, A₃) belonging to the G-protein-coupled receptor (GPCR) superfamily.
• GPCRs are increasingly recognized to form oligomeric complexes, including homomers and heteromers.

Purpose of the Study:

• To review evidence for the formation of adenosine receptor heteromers.
• To highlight the structural arrangements, specifically tetrameric complexes, of these heteromers.
• To discuss the functional diversity introduced by adenosine receptor heteromers in adenosinergic signaling.

Main Methods:

• Review of accumulated scientific literature over the past 20 years.
• Analysis of data demonstrating the co-expression and interaction of adenosine receptors.
• Focus on studies investigating the structural and functional properties of receptor heteromers.

Main Results:

• Evidence supports the existence of heteromers formed by specific adenosine receptor pairs: A₁/A_2A, A_2A/A_2B, and A_2A/A₃.
• These heteromers exhibit defined tetrameric structural arrangements.
• The formation of heteromers leads to novel functional outcomes in adenosine signaling.

Conclusions:

• Adenosine receptors frequently assemble into heteromeric complexes.
• These heteromeric structures, particularly tetramers, significantly expand the functional repertoire of adenosinergic signaling.
• Understanding adenosine receptor heteromers is crucial for deciphering complex cellular responses mediated by adenosine.