Engineering a Stable and Selective Peptide Blocker of the Kv1.3 Channel in T Lymphocytes

Pennington, MW; Beeton, C; Galea, CA; Smith, BJ; Chi, V; Monaghan, KP; Garcia, A; Rangaraju, S; Giuffrida, A; Plank, D; Crossley, G; Nugent, D; Khaytin, I; LeFievre, Y; Peshenko, I; Dixon, C; Chauhan, S; Orzel, A; Inoue, T; Hu, X; Moore, RV; Norton, RS; Chandy, KG

Author(s): Pennington, MW; Beeton, C; Galea, CA; Smith, BJ; Chi, V; Monaghan, KP; Garcia, A; Rangaraju, S; Giuffrida, A; Plank, D; Crossley, G; Nugent, D; Khaytin, I; LeFievre, Y; Peshenko, I; Dixon, C; Chauhan, S; Orzel, A; Inoue, T; Hu, X; Moore, RV; Norton, RS; Chandy, KG;
Details: Publication Year 2009-04,Volume 75,Issue #4,Page 762-773
Journal Title: MOLECULAR PHARMACOLOGY
Publication Type: Journal Article
Abstract: Kv1.3 potassium channels maintain the membrane potential of effector memory (T(EM)) T cells that are important mediators of multiple sclerosis, type 1 diabetes mellitus, and rheumatoid arthritis. The polypeptide ShK-170 (ShK-L5), containing an N-terminal phosphotyrosine extension of the Stichodactyla helianthus ShK toxin, is a potent and selective blocker of these channels. However, a stability study of ShK-170 showed minor pH-related hydrolysis and oxidation byproducts that were exacerbated by increasing temperatures. We therefore engineered a series of analogs to minimize the formation of these byproducts. The analog with the greatest stability, ShK-192, contains a nonhydrolyzable phosphotyrosine surrogate, a methionine isostere, and a C-terminal amide. ShK-192 shows the same overall fold as ShK, and there is no evidence of any interaction between the N-terminal adduct and the rest of the peptide. The docking configuration of ShK-192 in Kv1.3 shows the N-terminal para-phosphonophenylalanine group lying at the junction of two channel monomers to form a salt bridge with Lys(411) of the channel. ShK-192 blocks Kv1.3 with an IC(50) of 140 pM and exhibits greater than 100-fold selectivity over closely related channels. After a single subcutaneous injection of 100 mu g/kg, similar to 100 to 200 pM concentrations of active peptide is detectable in the blood of Lewis rats 24, 48, and 72 h after the injection. ShK-192 effectively inhibits the proliferation of T(EM) cells and suppresses delayed type hypersensitivity when administered at 10 or 100 mu g/kg by subcutaneous injection once daily. ShK-192 has potential as a therapeutic for autoimmune diseases mediated by T(EM) cells.
Publisher: AMER SOC PHARMACOLOGY EXPERIMENTAL THERAPEUTICS
Keywords: EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS; GATED K+ CHANNELS; MULTIPLE-SCLEROSIS; SHK TOXIN; POTASSIUM CHANNELS; SEA-ANEMONE; PERIPHERAL-BLOOD; RAT-BRAIN; CELLS; EXPRESSION
Publisher's Version: https://doi.org/10.1124/mol.108.052704
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2009-04-01 12:00:00