Structural basis of the activation of TRPV5 channels by long-chain acyl-Coenzyme-A

Lee BH, De Jesús Pérez JJ, Moiseenkova-Bell V, Rohacs T. Nat Commun. 2023 Sep 21;14(1):5883. doi: 10.1038/s41467-023-41577-z. 

Abstract

Long-chain acyl-coenzyme A (LC-CoA) is a crucial metabolic intermediate that plays important cellular regulatory roles, including activation and inhibition of ion channels. The structural basis of ion channel regulation by LC-CoA is not known. Transient receptor potential vanilloid 5 and 6 (TRPV5 and TRPV6) are epithelial calcium-selective ion channels. Here, we demonstrate that LC-CoA activates TRPV5 and TRPV6 in inside-out patches, and both exogenously supplied and endogenously produced LC-CoA can substitute for the natural ligand phosphatidylinositol 4,5-bisphosphate (PI(4,5)P₂) in maintaining channel activity in intact cells. Utilizing cryo-electron microscopy, we determined the structure of LC-CoA-bound TRPV5, revealing an open configuration with LC-CoA occupying the same binding site as PI(4,5)P₂ in previous studies. This is consistent with our finding that PI(4,5)P₂ could not further activate the channels in the presence of LC-CoA. Our data provide molecular insights into ion channel regulation by a metabolic signaling molecule.

Results

Activation of TRPV5 and TRPV6 by CoA species requires a long acyl chain

We studied the effect of long-chain acyl-CoA (LC-CoA) in excised inside-out patches on the rabbit TRPV5 and the human TRPV6 channels expressed in Xenopus laevis oocytes. These channels are known to require PI(4,5)P₂ for activity^15,17. Since LC-CoA and PI(4,5)P₂ have structural similarities such as three phosphate groups in the head group and one or two acyl chains (Fig. 1a, b), we hypothesized that LC-CoA can substitute for PI(4,5)P₂ in supporting TRPV5 and TRPV6 activity. To test this hypothesis, we examined the effect of different types of fatty acyl-CoA on both TRPV5 and TRPV6 (Fig. 1). As a control, water-soluble diC₈ PI(4,5)P₂ was used to reversibly activate the channels. Table 1 shows six different fatty acyl-CoA species used in the current study. Their names are represented as (chain length: number of the double bonds), for instance, octanoyl-CoA is denoted as C8:0 CoA.