UASt regulatory sequences drive expression of altered ci coding sequence (amino acid replacements S838A, S892A and D843A) in which the phosphorylation of Pka-C1 site 2 theoretically primes three consecutive phosphorylations at sgg sites to produce a DpSGIHpS motif, in which the first residue (codon 843) is changed to alanine to give ASGIHpS, fused at the N-terminal with a composite 3xTag:FLAG/3xTag:HA tag and at the C-terminal by a Tag:MYC tag.