Ligand-gated ion channels are transmembrane proteins that respond to a variety of transmitters, including acetylcholine, γ-aminobutyric acid (GABA), glycine, and glutamate [1, 2]. These proteins play key roles in neurotransmission and are typically found in the nervous system and at neuromuscular junctions . Recently, acetylcholine receptor family members also have been found in nonneuronal cells, including macrophages , keratinocytes , bronchial epithelial cells , and endothelial cells of arteries . The function of these channels in nonneuronal cells in mammals remains to be elucidated, though it has been shown that the acetylcholine receptor α7 subunit is required for acetylcholine-mediated inhibition of tumor necrosis factor release by activated macrophages . We show that cup-4, a gene required for efficient endocytosis of fluids by C. elegans coelomocytes, encodes a protein that is homologous to ligand-gated ion channels, with the highest degree of similarity to nicotinic acetylcholine receptors. Worms lacking CUP-4 have reduced phosphatidylinositol 4,5-bisphosphate levels at the plasma membrane, suggesting that CUP-4 regulates endocytosis through modulation of phospholipase C activity.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Agricultural and Biological Sciences(all)