441: Evolutionary mapping of Cav1.3 functional sites

Tang X et al., PNAS - The authors apply an evolutionary sequence-covariation model to the Cav1.3 (CACNA1D) α1-subunit, map predicted pathogenicity onto structural models, and validate five predicted sites by patch-clamp electrophysiology and structural analysis. Predictions recapitulate known functional regions, reveal previously unrecognized clusters, and the tested variants produce diverse functional outcomes from nonconducting channels to gain- and loss-of-function gating changes. Key terms: Cav1.3, evolutionary modeling, CACNA1D, voltage-gated calcium channel, variant pathogenicity.

Study Highlights:
An evolutionary epistasis model predicted context-dependent conserved residues across Cav1.3 and recapitulated known functional sites. Mapping scores onto structural models highlighted novel clusters outside classical pore and voltage-sensor regions. Electrophysiological testing of five predicted variants confirmed diverse functional effects, including nonconducting (N745A), left-shifted activation (S635I, A376V, R1401A), and right-shifted or slowed gating (F1362A; Q1156E increased inactivation). The combined evolutionary, structural, and biophysical approach provides a scalable framework to prioritize and interpret CACNA1D variants.

Conclusion:
Evolutionary sequence-covariation combined with structural modeling and electrophysiology identifies novel functionally critical residues across Cav1.3 and enables rapid prioritization of pathogenic CACNA1D variants; the approach is generalizable to other ion channels but requires experimental follow-up to define gain- versus loss-of-function.

Music:
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Article title:
Identification of novel functional sites in the Cav1.3 calcium channel α1-subunit using evolutionary modeling

First author:
Tang X

Journal:
PNAS

DOI:
10.1073/pnas.2602636123

Reference:
Tang X, Hermenean HC, Yakimchyka A, Tuluc P, Ortner NJ, Liedl KR. Identification of novel functional sites in the Cav1.3 calcium channel α1-subunit using evolutionary modeling. PNAS. 2026;123(32):e2602636123. doi:10.1073/pnas.2602636123

License:
This episode is based on an open-access article published under the Creative Commons Attribution 4.0 International License (CC BY 4.0) – https://creativecommons.org/licenses/by/4.0/

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Episode link: https://basebybase.com/episodes/evolutionary-modeling-cav1-3-functional-sites

QC:
This episode was checked against the original article PDF and publication metadata for the episode release published on 2026-08-14.

QC Scope:
- article metadata and core scientific claims from the narration
- excludes analogies, intro/outro, and music
- transcript coverage: Audited the core scientific sections: evolutionary modeling predictions, structure mapping onto Cav1.3 models, electrophysiology validation in tsA-201 cells, and the functional effects of Cav1.3 variants (N745A, S635I, A376V, F1362A, R1401A, Q1156E); also reviewed limitations and clinical interpretation.
- transcript topics: Evolutionary sequence covariation and context-dependent conservation in Cav1.3; Mapping pathogenicity scores onto Cav1.3 cryo-EM structures; Electrophysiological validation of Cav1.3 variants in tsA-201 cells; Functional consequences of specific Cav1.3 variants (N745A, S635I, A376V, F1362A, R1401A, Q1156E); Limitations...