UASt regulatory sequences drive expression of comm in which all Lys residues that serve as Ubiquitin acceptor sites have been mutated to Arg residues (amino acid replacements K162R, K167R, K168R, K171R, K248R, K269R, K275R, K278R, K280R and K291R). The coding sequence is tagged at the C-terminal end with a triple Tag:HA tag.