PI(4,5)P2 regulates the gating of NaV1.4 channels

Gada, Kirin; Kamuene, Jordie M.; Chandrashekar, Aishwarya; Kissell, R Charles; Yauch, Anne; Plant, Leigh D.

doi:10.1085/jgp.202213255

Cited by 10 publications

(8 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These results demonstrate that I Na is affected only when SAP97 mediates the Na V 1.5 and Kir2.1 C122Y multiprotein complex through PDZ domains. 54–57 Interestingly, a recent study has shown that PIP 2 is a negative regulator of gating properties of NaV1.4 channels, 58 suggesting that it may also be negatively regulating Na V 1.5 in our ATS1 mouse model. However, further studies are needed to elucidate the precise mechanisms underlying the impairment of sodium channel activity triggered by Kir2.1 C122Y , which does not affect channel trafficking.…”

Section: Discussionmentioning

confidence: 82%

Extracellular Kir2.1 ^C122Y Mutant Upsets Kir2.1-PIP ₂ Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

Cruz,

Macías,

Moreno-Manuel

et al. 2024

Circulation Research

View full text Add to dashboard Cite

BACKGROUND: Andersen-Tawil syndrome type 1 is a rare heritable disease caused by mutations in the gene coding the strong inwardly rectifying K + channel Kir2.1. The extracellular Cys (cysteine) 122 -to-Cys 154 disulfide bond in the channel structure is crucial for proper folding but has not been associated with correct channel function at the membrane. We evaluated whether a human mutation at the Cys 122 -to-Cys 154 disulfide bridge leads to Kir2.1 channel dysfunction and arrhythmias by reorganizing the overall Kir2.1 channel structure and destabilizing its open state. METHODS AND RESULTS: We identified a Kir2.1 loss-of-function Cys 122 mutation (c.366 A>T; p.Cys122Tyr) in an Andersen-Tawil syndrome type 1 family. We generated a cardiac-specific mouse model expressing the Kir2.1 C122Y that recapitulated the abnormal ECG features of Andersen-Tawil syndrome type 1 independently of sex, including corrected QT prolongation, conduction defects, and increased arrhythmia susceptibility. Isolated Kir2.1 C122Y cardiomyocytes showed significantly reduced inwardly rectifier K + (I K1 ) and inward Na + (I Na ) current densities independently of normal trafficking to and localization at the sarcolemma and the sarcoplasmic reticulum. However, molecular dynamics predicted that the C122Y mutation provoked a conformational change over the 2000-ns simulation, characterized by a greater loss of hydrogen bonds between Kir2.1 and phosphatidylinositol 4,5-bisphosphate than WT. Therefore, the phosphatidylinositol 4,5-bisphosphate–binding pocket was destabilized, resulting in a lower conductance state compared with WT. Accordingly, on inside-out patch clamping, the C122Y mutation significantly blunted Kir2.1 sensitivity to increasing phosphatidylinositol 4,5-bisphosphate concentrations. In addition, the Kir2.1 C122Y mutation resulted in channelosome degradation, demonstrating temporal instability of both Kir2.1 and Na V 1.5 proteins. CONCLUSIONS: The extracellular Cys 122 -to-Cys 154 disulfide bond in the tridimensional Kir2.1 channel structure is essential for the channel function. We demonstrate that breaking disulfide bonds in the extracellular domain disrupts phosphatidylinositol 4,5-bisphosphate–dependent regulation, leading to channel dysfunction and defects in Kir2.1 energetic stability. The mutation also alters functional expression of the Na V 1.5 channel and ultimately leads to conduction disturbances and life-threatening arrhythmia characteristic of Andersen-Tawil syndrome type 1.

show abstract

Section: Discussionmentioning

confidence: 82%

Extracellular Kir2.1 ^C122Y Mutant Upsets Kir2.1-PIP ₂ Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

Cruz,

Macías,

Moreno-Manuel

et al. 2024

Circulation Research

View full text Add to dashboard Cite

show abstract

“…The leftward shift in voltage dependence of inactivation is less pronounced when PI(4,5)P 2 is converted to PI(4)P rather than completely dephosphorylated to PI ( Gada et al, 2023 ). This suggests that PI(4)P may play a compensatory role when PI(4,5)P 2 is not present.…”

Section: Discussionmentioning

confidence: 94%

“…( B ) Naᵥ1.4 structure (6agf) showing the four domain-swapped voltage-sensing domains (VSDs I–IV), pore, and DIII–IV linker on the intracellular side. ( C ) Summary of PI(4,5)P 2 effects on transitions between Naᵥ channel functional states ( Gada et al, 2023 ). ( D ) Structure of the PI(4,5)P 2 headgroup with the 4’- and 5’-phosphates indicated.…”

Section: Introductionmentioning

confidence: 99%

“…Recent experiments show that Naᵥ1.4 channel kinetics and voltage dependence are modulated by PI(4,5)P 2 ( Gada et al, 2023 ). PI(4,5)P 2 inhibits Naᵥ1.4 by causing a depolarizing shift in voltage dependence of activation, accelerating transition to the inactivated state and slowing recovery from inactivation, resulting in reduced peak current and suppression of late current (summarized in Figure 1C ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels

Lin,

Tao,

Champion

et al. 2024

eLife

View full text Add to dashboard Cite

Voltage gated sodium channels (Nav) are membrane proteins which open to facilitate the inward flux of sodium ions into excitable cells. In response to stimuli, Nav channels undergo a transition from the resting, closed state to an open state which allows ion influx, before rapidly inactivating. Dysregulation of this functional cycle due to mutations leads to diseases including epilepsy, pain conditions and cardiac disorders, making Nav channels a significant pharmacological target. Phosphoinositides are important lipid cofactors for ion channel function. The phosphoinositide PI(4,5)P2 decreases Nav1.4 activity by increasing the difficulty of channel opening, accelerating fast activation and slowing recovery from fast inactivation. Using multiscale molecular dynamics simulations, we show that PI(4,5)P2 binds stably to inactivated Nav at a conserved site within the DIV S4-S5 linker, which couples the voltage sensing domain (VSD) to the pore. As the Nav C-terminal domain is proposed to also bind here during recovery from inactivation, we hypothesise that PI(4,5)P2 prolongs inactivation by competing to bind to this site. In atomistic simulations, PI(4,5)P2 reduces the mobility of both the DIV S4-S5 linker and the DIII-IV linker, responsible for fast inactivation, slowing the conformational changes required for the channel to recover to the resting state. We further show that in a resting state Nav model, phosphoinositides bind to VSD gating charges, which may anchor them and impede VSD activation. Our results provide a mechanism by which phosphoinositides alter the voltage dependence of activation and the rate of recovery from inactivation, an important step for the development of novel therapies to treat Nav-related diseases.

show abstract

“…As an alternative means of rapid PIP 2 depletion which has, in the TRP field so far, just been applied to the study of TRPC channels [ 75 , 76 ], we took advantage of a light-activated phosphatase system developed by Idevall-Hagren and colleagues (2012) [ 1 ]. Apart from TRPC4 and TRPC5 homomeric channels, as well as TRPC1/4 or TRPC1/5 heterotetramers [ 75 , 76 ], the concerning system has already been implemented to modulate KCNQ2/3 channel activity [ 1 ] and, among others, the epithelial sodium (Na + ) channel ENaC [ 77 , 78 ] or NaV1.4 [ 79 ]. The respective approach is based on the reversible dimerization between the plant-derived proteins cryptochrome 2 (CRY2) and the transcription factor CIB1 (cryptochrome-interacting basic helix–loop–helix 1) upon blue light illumination (BLI; ~440–490 nm) [ 1 , 79 ].…”

Section: Resultsmentioning

confidence: 99%

Bidirectional Allosteric Coupling between PIP2 Binding and the Pore of the Oncochannel TRPV6

Humer,

Radiskovic,

Horváti

et al. 2024

IJMS

View full text Add to dashboard Cite

The epithelial ion channel TRPV6 plays a pivotal role in calcium homeostasis. Channel function is intricately regulated at different stages, involving the lipid phosphatidylinositol-4,5-bisphosphate (PIP2). Given that dysregulation of TRPV6 is associated with various diseases, including different types of cancer, there is a compelling need for its pharmacological targeting. Structural studies provide insights on how TRPV6 is affected by different inhibitors, with some binding to sites else occupied by lipids. These include the small molecule cis-22a, which, however, also binds to and thereby blocks the pore. By combining calcium imaging, electrophysiology and optogenetics, we identified residues within the pore and the lipid binding site that are relevant for regulation by cis-22a and PIP2 in a bidirectional manner. Yet, mutation of the cytosolic pore exit reduced inhibition by cis-22a but preserved sensitivity to PIP2 depletion. Our data underscore allosteric communication between the lipid binding site and the pore and vice versa for most sites along the pore.

show abstract

PI(4,5)P2 regulates the gating of NaV1.4 channels

Cited by 10 publications

References 52 publications

Extracellular Kir2.1 ^C122Y Mutant Upsets Kir2.1-PIP ₂ Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

Extracellular Kir2.1 ^C122Y Mutant Upsets Kir2.1-PIP ₂ Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels

Bidirectional Allosteric Coupling between PIP2 Binding and the Pore of the Oncochannel TRPV6

Contact Info

Product

Resources

About

PI(4,5)P2 regulates the gating of NaV1.4 channels

Cited by 10 publications

References 52 publications

Extracellular Kir2.1 C122Y Mutant Upsets Kir2.1-PIP 2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

Extracellular Kir2.1 C122Y Mutant Upsets Kir2.1-PIP 2 Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels

Bidirectional Allosteric Coupling between PIP2 Binding and the Pore of the Oncochannel TRPV6

Contact Info

Product

Resources

About

Extracellular Kir2.1 ^C122Y Mutant Upsets Kir2.1-PIP ₂ Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome

Extracellular Kir2.1 ^C122Y Mutant Upsets Kir2.1-PIP ₂ Bonds and Is Arrhythmogenic in Andersen-Tawil Syndrome