Diacylglycerol Activates the Drosophila Light Sensitive Channel TRPL Expressed in HEK Cells

• Published in: International journal of molecular sciences 2023-03, Vol.24 (7), p.6289
• Main Authors: Rhodes-Mordov, Elisheva, Brandwine-Shemmer, Tal, Zaguri, Rachel, Gutorov, Rita, Peters, Maximilian, Minke, Baruch
• Format: Article
• Language: English
• Subjects: 1-oleoyl-2-acetyl-sn-glycerol (OAG); 3-hydroxypropane-1,2-diylbis(4-(4-((E)-(4-butylphenyl) diazenyl) phenyl; Animals; Cell activation; Channels; Cytosol; Diacylglycerol (DAG); Diglycerides; Diglycerides - metabolism; Drosophila; Drosophila - metabolism; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Drosophila TRP/TRPL channels; Fruit flies; Glycerol; Hypotheses; Insects; Kinases; Light; Localization; Membranes - metabolism; Mutation; OptoDArG; Phosphatidylinositol; Phosphatidylinositol 4,5-diphosphate; Phosphatidylinositols; Phospholipase C; phospholipase C (PLC); Physiology; Transient Receptor Potential Channels - metabolism; Transient receptor potential proteins; Ultraviolet radiation
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms24076289

Physiological activation by light of the TRP and TRP-like (TRPL) channels requires the activation of phospholipase Cβ (PLC). The hydrolysis of phosphatidylinositol 4,5, bisphosphate (PIP ) by PLC is a crucial step in the still-unclear light activation, while the generation of Diacylglycerol (DAG) by PLC seems to be involved. In this study, we re-examined the ability of a DAG analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) to activate the TRPL channels expressed in HEK cells. Unlike previous studies, we added OAG into the cytosol via a patch-clamp pipette and observed robust activation of the expressed TRPL channels. However, TRPL channel activation was much slower than the physiologically activated TRPL by light. Therefore, we used a picosecond-fast optically activated DAG analogue, OptoDArG. Inactive OptoDArG was added into the intracellular solution with the patch-clamp pipette, and it slowly accumulated on the surface membrane of the recorded HEK cell in the dark. A fast application of intense UV light to the recorded cell resulted in a robust and relatively fast TRPL-dependent current that was greatly accelerated by the constitutively active TRPL pore-region mutation. However, this current of the mutant channel was still considerably slower than the native light-induced TRPL current, suggesting that DAG alone is not sufficient for TRPL channel activation under physiological conditions.