Yeast cells were co-transformed with pGBT9-ΔSS-HtrA1 and pACT2 vector containing cDNA for CoxVa, LRP9, PAR6B, CAST, mKIAA0769, GM130, Cdyl (upper lane of each panel) or their mutants that lacked the C-terminal 4 amino acids (lower lane of each panel). The transformants were streaked on an agar plate with (upper panels) or without (lower panels) histidine, containing either 5 mM (right-hand panels) or no (left hand panels) 3-AT. All yeast clones transformed with these wild-type prey cDNA required the presence of the bait HtrA1 cDNA for growth on His− plates (results not shown).