Fig. 5. Arabidopsis PIR and human SRA1 have similar RHO-family GTPase binding activities. (A) PIR and human SRA1 bind interchangeably to plant and animal RHO-family GTPases in the yeast two-hybrid assay. The bait and prey plasmids co-transformed into yeast are listed to the left of the corresponding patches and ß-galactosidase assay results. (B) PIR shows nucleotide-selectivity for interaction with ROP2 in yeast two-hybrid system. The bait and prey plasmids co-transformed into yeast are described to the left as in A.