Figure 4.

Mapping BTI Protein Domains Necessary for Interaction with VirB2, BTI, and AtRAB8 in Yeast.

(A) Hydropathy profile of BTI1 protein using the Prediction of Transmembrane Regions and Orientation program (Hofmann and Stoffel, 1993). The C-terminal region of BTI1 protein contains two hydrophobic domains. The N-terminal region of BTI1 has one hydrophilic domain and is variable among the three BTI proteins. The arrows indicate the putative membrane domains of BTI1 protein.

(B) Schematic diagram of the various BTI1 protein-deletion mutants. The dotted lines indicate the deleted region of each mutant protein.

(C) Results of protein-interaction experiments in yeast. Only mutant protein BTI1-E interacts with VirB2, BTI1, BTI2, BTI3, and AtRAB8. Construction of the mutant bti1 genes and the yeast interaction assays are described in Materials and Methods.