ATP stimulates pannexin 1 internalization to endosomal compartments

Area of Science:

• Cell Biology
• Neuroscience
• Biochemistry

Background:

• Pannexin 1 (Panx1) channels release ATP, a key signaling molecule.
• Panx1's role in cellular processes is significant, especially when extracellular ATP levels rise.

Purpose of the Study:

• To investigate how extracellular ATP influences Panx1 channel localization.
• To understand the mechanisms and implications of ATP-induced Panx1 internalization.

Main Methods:

• Utilized Panx1-EGFP fusion protein to track channel internalization.
• Investigated the role of ATP hydrolysis, P2X receptors, and specific Panx1 residues (Trp74).
• Assessed the dependence on cholesterol and endocytic machinery (clathrin, caveolin, dynamin).

Main Results:

• Extracellular ATP rapidly induced Panx1-EGFP internalization.
• Hydrolyzable ATP was the most potent stimulator.
• Internalization involved P2X receptors or Trp74, was cholesterol-dependent, but independent of clathrin, caveolin, and dynamin.
• Panx1 was found in degradation and recycling endosomes, suggesting altered trafficking upon ATP elevation.

Conclusions:

• Extracellular ATP actively regulates Panx1 surface expression through internalization.
• This mechanism provides new insights into Panx1 function in health and disease, particularly in conditions with elevated ATP.
• Identified endosomal trafficking of Panx1 as a novel regulatory pathway.