Figure 1.

Diagram of mutant ZO-1 proteins. The domain structure of ZO-1 is shown at the top, with the dotted box denoting the boundaries of the PDZ domains, the hatched box the Src homology 3 domain, and the checkered box the GuK domain. Mutants are designated by their amino acids included or deleted (Δ). ZO-1^1–263, ZO-1^1–422, ZO-1^1–794, and ZO-1^1–1745 (full length) were each tagged with seven c-myc epitopes as described in MATERIALS AND METHODS. ZO-1^Δ615–812 (lacking the GuK domain) was tagged with the FLAG epitope.