Screening assay for insecticides

A method for identifying an insecticidal active compound that reduces the activity of an insect voltage-gated potassium channel Sha1 (Shaker cognate 1 or Shaker-like) and its accessory protein KChIP (potassium channel-interacting protein) which method comprises:

• a) assembling in a membrane polypeptides, originally not present in said membrane, having the activity of an insect voltage-gated potassium channel Sha1 (Shaker cognate 1 or Shaker-like) and its accessory protein KChIP (potassium channel-interacting protein),
• b) applying at one side of the membrane the compound suspected of having the ability to inhibit the activity of said polypeptides which are originally not present in said membrane,
• c) determining the activity of said polypeptides,
• d) identifying the compound applied in (b) that reduces the activity of said polypeptides as an insecticidal active compound;
• and
• e) selecting the compound identified in step d) as the insecticidal active compound;
• wherein said polypeptides having the activity of Sha1 are encoded by one or more nucleic acid molecules selected from the group consisting of:
• a) a nucleic acid molecule encoding the polypeptide shown in SEQ ID NO:
• 2, or a polypeptide of a ShaI_delN mutant which is a polypeptide with an N-terminal deletion of amino acids 2-40 of the polypeptide shown in SEQ ID NO:
• 2;
• b) a nucleic acid molecule shown in SEQ ID NO:
• 1 or a nucleic acid molecule which is a nucleic acid molecule with a deletion of the coding region in SEQ ID NO:
• 1 that encodes amino acids 2-40 of the polypeptide shown in SEQ ID NO:
• 2;
• c) a nucleic acid molecule encoding a polypeptide having at least 80% identity with the amino acid sequence of the polypeptide encoded by the nucleic acid molecule of (a) to (b) and having the activity of a voltage-gated potassium channel Sha1 (Shaker cognate 1 or Shaker-like);
• and
• wherein said polypeptides having the activity of KChIP are encoded by one or more nucleic acid molecules selected from the group consisting of:
• a) a nucleic acid molecule encoding a polypeptide with KChIP activity as shown in SEQ ID NO:
• 26;
• b) a nucleic acid molecule shown in SEQ ID NO:
• 25;
• (c) a nucleic acid molecule encoding a polypeptide having at least 80% identity with the amino acid sequence of the polypeptide encoded by the nucleic acid molecule of (a) to (b) and having the activity of a voltage-gated potassium channel accessory protein KChIP (potassium channel-interacting protein).