Interaction of Synthetic Human SLURP-1 with the Nicotinic Acetylcholine Receptors

Thomas Durek (1) , Irina V Shelukhina (2) , Han-Shen Tae (3) , Panumart Thongyoo (1, 4) , Ekaterina N Spirova (2) , Denis S Kudryavtsev (2) , Igor E Kasheverov (2) , Grazyna Faure (5) , Pierre-Jean Corringer (5) , David J Craik (1) , David J. Adams (3) , Victor I Tsetlin (2)

1 Institute for Molecular Bioscience
2 IBCh RAS - Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry
3 University of Wollongong [Australia]
4 TU - Thammasat University
5 Récepteurs Canaux - Channel Receptors

Human SLURP-1 is a secreted protein of the Ly6/uPAR/three-finger neurotoxin family that co-localizes with nicotinic acetylcholine receptors (nAChRs) and modulates their functions. Conflicting biological activities of SLURP-1 at various nAChR subtypes have been based on heterologously produced SLURP-1 containing N- and/or C-terminal extensions. Here, we report the chemical synthesis of the 81 amino acid residue human SLURP-1 protein, characterization of its 3D structure by NMR, and its biological activity at nAChR subtypes. Radioligand assays indicated that synthetic SLURP-1 did not compete with [ 125 I]-α-bungarotoxin (α-Bgt) binding to human neuronal α7 and Torpedo californica muscle-type nAChRs, nor to mollusk acetylcholine binding proteins (AChBP). Inhibition of human α7-mediated currents only occurred in the presence of the allosteric modulator PNU120596. In contrast, we observed robust SLURP-1 mediated inhibition of human α3β4, α4β4, α3β2 nAChRs, as well as human and rat α9α10 nAChRs. SLURP-1 inhibition of α9α10 nAChRs was accentuated at higher ACh concentrations, indicating an allosteric binding mechanism. Our results are discussed in the context of recent studies on heterologously produced SLURP-1 and indicate that N-terminal extensions of SLURP-1 may affect its activity and selectivity on its targets. In this respect, synthetic SLURP-1 appears to be a better probe for structure-function studies.

Domaines: Sciences du Vivant [q-bio]; Chimie

Thomas Durek, Irina V Shelukhina, Han-Shen Tae, Panumart Thongyoo, Ekaterina N Spirova, et al.. Interaction of Synthetic Human SLURP-1 with the Nicotinic Acetylcholine Receptors. Scientific Reports, 2017, 7 (1), pp.16606. ⟨10.1038/s41598-017-16809-0⟩. ⟨pasteur-04102878⟩