Dual regulation of TRPV1 channels by phosphatidylinositol via functionally distinct binding sites
| Autor: | Marina A. Kasimova, Bo Hyun Lee, Eleonora Gianti, Tibor Rohacs, Aysenur Yazici, Vincenzo Carnevale |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Protein Conformation TRPV1 TRPV Cation Channels Molecular Dynamics Simulation Phosphatidylinositols Biochemistry TIRF total internal reflection fluorescence 03 medical and health sciences chemistry.chemical_compound Transient receptor potential channel PLC phospholipase C TRP channel TRPV1 transient receptor potential vanilloid 1 Phosphatidylinositol Binding site Molecular Biology Ion channel Binding Sites 030102 biochemistry & molecular biology Phospholipase C Chemistry musculoskeletal neural and ocular physiology phosphoinositides Cell Biology MD molecular dynamics molecular dynamics Cell biology 030104 developmental biology nervous system Phosphatidylinositol 4 5-bisphosphate Competitive antagonist ion channel PtdIns phosphatidylinositol Mutation PtdIns(4 5)P2 phosphatidylinositol 4 5-bisphosphate lipids (amino acids peptides and proteins) diC8 dioctanoyl Research Article TRP transient receptor potential |
| Zdroj: | The Journal of Biological Chemistry |
| ISSN: | 0021-9258 |
| DOI: | 10.1016/j.jbc.2021.100573 |
| Popis: | Regulation of the heat- and capsaicin-activated transient receptor potential vanilloid 1 (TRPV1) channel by phosphoinositides is complex and controversial. In the most recent TRPV1 cryo-EM structure, endogenous phosphatidylinositol (PtdIns) was detected in the vanilloid binding site, and phosphoinositides were proposed to act as competitive vanilloid antagonists. This model is difficult to reconcile with phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] being a well-established positive regulator of TRPV1. Here we show that in the presence of PtdIns(4,5)P2 in excised patches, PtdIns, but not PtdIns(4)P, partially inhibited TRPV1 activity at low, but not at high capsaicin concentrations. This is consistent with PtdIns acting as a competitive vanilloid antagonist. However, in the absence of PtdIns(4,5)P2, PtdIns partially stimulated TRPV1 activity. We computationally identified residues, which are in contact with PtdIns, but not with capsaicin in the vanilloid binding site. The I703A mutant of TRPV1 showed increased sensitivity to capsaicin, as expected when removing the effect of an endogenous competitive antagonist. I703A was not inhibited by PtdIns in the presence of PtdIns(4,5)P2, but it was still activated by PtdIns in the absence of PtdIns(4,5)P2 indicating that inhibition, but not activation by PtdIns proceeds via the vanilloid binding site. In molecular dynamics simulations, PtdIns was more stable than PtdIns(4,5)P2 in this inhibitory site, whereas PtdIns(4,5)P2 was more stable than PtdIns in a previously identified, nonoverlapping, putative activating binding site. Our data indicate that phosphoinositides regulate channel activity via functionally distinct binding sites, which may explain some of the complexities of the effects of these lipids on TRPV1. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|