Effects of intersubunit amino acid substitutions on GABA receptor sensitivity to the ectoparasiticide fluralaner.
Pestic Biochem Physiol
; 163: 123-129, 2020 Feb.
Article
em En
| MEDLINE
| ID: mdl-31973848
ABSTRACT
The isoxazoline ectoparasiticide fluralaner exerts antiparasitic effects by inhibiting the function of γ-aminobutyric acid (GABA) receptors (GABARs). The present study was conducted to identify the amino acid residues that contribute to the high sensitivity of insect GABARs to fluralaner. We generated housefly (Musca domestica) GABARs with amino acid substitutions in the first through third α-helical transmembrane segments (TM1-TM3) of the RDL subunit using site-directed mutagenesis and examined the effects of the substitutions on the sensitivity of GABARs expressed in Xenopus oocytes to fluralaner using two-electrode voltage clamp electrophysiology. The Q271L substitution in TM1 caused a significant reduction in the sensitivity to fluralaner. Although the I274A and I274F substitutions in TM1 did not affect fluralaner sensitivity, the I274C substitution significantly enhanced the sensitivity to fluralaner. In contrast, the L278C substitution in TM1 reduced fluralaner sensitivity. Substitutions of Gly333 in TM3 led to substantial reductions in the sensitivity to fluralaner. These findings indicate that Gln271, Ile274, Leu278, and Gly333, which are situated in the outer half of the transmembrane subunit interface, are closely related to the antagonism of GABARs by fluralaner.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Receptores de GABA
/
Moscas Domésticas
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article