Fig. 3. Mapping of the LPP interaction site in -actinin by the two-hybrid system. The yeast reporter strain Y190 was cotransfected with a prey vector encoding the N-terminus of LPP (residues 1-61) and different bait vectors encoding various fragments of -actinin as indicated. Two-hybrid interactions were analyzed by growth on histidine, tryptophan and leucine-deficient plates. Positive interactions (+) were verified by the colony filter lift assay. Interactions of the same -actinin fragments with the N-terminus of zyxin (residues 1-42) were analyzed in parallel experiments. Note that all -actinin fragments that revealed a positive interaction are able to form dimers in vitro (Li and Trueb, 2001). CH, region containing calponin homology domains; SPEC, region containing spectrin-like repeats; EF, region containing EF hands.