Poster Presentation The 16th Australian Peptide Conference 2025

Evaluating Kv1.3-Selective Inhibitor Activity Across Kv1.3/Kv1.x Heterotetramers: Electrophysiological Characterisation and Structural Modelling (#202)

Yuandi Hu 1 , Umair M Naseem 2 , Gyorgy Panyi 2 , David K Chalmers 1 , Ray S Norton 1
  1. Monash Institute of Pharmaceutical Sciences, Melbourne, VIC, Australia
  2. Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary

The voltage-gated potassium channel Kv1.3 is a validated therapeutic target for neuroinflammatory and autoimmune diseases.1 While most channels in the Kv1.x subfamily are tetramers composed of four identical subunits, Kv1.x subunits can co-assemble into heterotetrameric channels. For example, Kv1.3/Kv1.5 heterotetramers have been identified in macrophages and microglia. Venom-derived peptides represent a promising class of Kv1.3 inhibitors. Among these inhibitors, ShK-186 (dalazatide) is a 35-residue peptide derived from the sea anemone toxin Stichodactyla helianthus, that is currently undergoing phase II clinical trials for multiple sclerosis and rheumatoid arthritis.2 While Kv1.3-selective inhibitors like ShK-186 have been extensively characterised against Kv1.x homotetramers, their affinity toward physiologically relevant heterotetrameric assemblies remains unclear. In this study, we used whole-cell patch-clamp electrophysiology to assess the inhibitory activity of three Kv1.3-selective peptides (Vm24, HsTX1[R14A], and ShK-186) against Kv1.3/Kv1.x heterotetramers (Kv1.1–Kv1.6). We built structural models of representative heterotetramers using AlphaFold-Multimer, with particular focus on Kv1.3/Kv1.5 heterotetramers. Kv1.3-selective peptides were then docked into these complexes. The results of our electrophysiological and structural findings will be presented. This integrated experimental and computational study will help to understand of how Kv1.3-selective inhibitors engage heteromeric Kv1.x channels and underpin the design of next-generation Kv1.3-targeted peptides with bespoke selectivity profiles.

 

1. Tajti, G., Wai, D.C., Panyi, G., and Norton, R.S. The voltage-gated potassium channel KV1. 3 as a therapeutic target for venom-derived peptides. Biochem. Pharmacol. 2020, 181, 114146.

2. Pennington, M.W., Beeton, C., Galea, C.A., Smith, B.J., Chi, V., Monaghan, K.P., Garcia, A., Rangaraju, S., Giuffrida, A., and Plank, D. Engineering a stable and selective peptide blocker of the Kv1. 3 channel in T lymphocytes. Mol. Pharmacol. 2009, 75, 762-773.