# Allosteric Regulation of KCNH Channels

> **NIH NIH R01** · UNIVERSITY OF WISCONSIN-MADISON · 2020 · $430,543

## Abstract

KCNH channels such as EAG and hERG serve important physiological roles in the nervous system and are
targets for disease such as epilepsy and cardiac arrhythmia. They are emerging biomarkers for malignancy
and proliferation in a wide range of blood cancers and tumors. Unique to this family of channels are highly
conserved intracellular domains that have evolved over the millennia to serve unique physiological roles. In the
previous project period, the PI and Co-I resolved details about the role of the C-terminal cyclic nucleotide-
binding homology domain (CNBhD) in gating, and provided first insights into dynamic behavior of the Per-Arnt-
Sim (PAS) domain. We generated new reagents in the form of single-chain fragment (scFv) antibodies, which
we showed exerted therapeutic potential with a beneficial ceiling effect that could confer protection against
arrhythmia. Here we have developed a new model for dynamic modulation of gating via the interactions of the
PAS domain, CNBhD and the C-linker based on recent cryo-EM structures of closed and open channels. We
will test hypotheses emerging from the EAG1 cryo-EM structure with calmodulin (CaM) to elucidate the
mechanism by which CaM inhibits EAG1 channel function. We will test a new hypothesis for how the PAS-cap
modulates channel gating scFv antibodies as tools to monitor state-dependent changes in accessibility and by
immobilizing the domain by crosslinking substituted unnatural amino acids. We will count the number of PAS
domains in heteromeric hERG channels comprising PAS-containing (1a) and PAS-less (1b) subunits in both
heterologous systems and native tissues. To answer this long-standing question of hERG stoichiometry, we
will use isoform-specific scFvs in combination with a novel single-molecule technology that can detect
individual binding events of antibodies with modest affinities to untagged channel subunits and is equally
applicable to native tissues. The broad range of biochemical, biophysical and functional approaches reflect
highly complementary strengths of the participating laboratories. Given the importance of the KCNH family of
channels to so many physiological and disease processes, the advances expected from the work here, made
possible by recent cutting-edge conceptual and technical developments, will have broad implications.

## Key facts

- **NIH application ID:** 9988964
- **Project number:** 5R01NS081320-07
- **Recipient organization:** UNIVERSITY OF WISCONSIN-MADISON
- **Principal Investigator:** Gail A Robertson
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $430,543
- **Award type:** 5
- **Project period:** 2012-09-30 → 2023-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9988964

## Citation

> US National Institutes of Health, RePORTER application 9988964, Allosteric Regulation of KCNH Channels (5R01NS081320-07). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9988964. Licensed CC0.

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