ATP release via anion channels.

Area of Science:

• Cell Biology
• Molecular Physiology
• Biochemistry

Background:

• Adenosine triphosphate (ATP) functions as both an intracellular energy source and an extracellular signaling molecule.
• ATP release from cells occurs through various purinergic efflux pathways.
• At physiological pH, ATP exists as an anion and can potentially exit cells via anion channels.

Purpose of the Study:

• To review experimental evidence for and against the release of ATP through anion channels.
• To evaluate the roles of specific anion channels, including CFTR, VSOR, and maxi-anion channels, in ATP efflux.
• To discuss other channels and transporters involved in regulated ATP release.

Main Methods:

• Literature review of experimental data on ATP release mechanisms.
• Analysis of evidence supporting or refuting ATP passage through specific anion channels.
• Examination of channel characteristics, pharmacology, and functional responses to cellular stress.

Main Results:

• Evidence suggests CFTR is a potential ATP release pathway, but non-CFTR currents also exist.
• Volume-sensitive outwardly rectifying (VSOR) chloride channels may accommodate ATP, but their role in significant ATP release is debated.
• Maxi-anion channels, with wide pores and ATP-binding sites, are strongly implicated in ATP release under various stress conditions.

Conclusions:

• Multiple anion channels are implicated in cellular ATP release.
• Maxi-anion channels represent a significant and well-characterized pathway for extracellular ATP signaling.
• Further research is needed to fully elucidate the roles of various channels and transporters in regulated ATP efflux.