Actomyosin organization in claudin/JAM-A KO cells. (A–C) F-actin/myosin IIA/ZO-1 triple staining in MDCK II cells. (A′–C′) F-actin/myosin IIA/ZO-1 triple staining in claudin/JAM-A KO cells. It should be noted that the circumferential actin bundles were extensively developed. (D and E) Myosin IIB/ZO-1 double staining in MDCK II cells. (D′ and E′) Myosin IIB/ZO-1 double staining in claudin/JAM-A KO cells. Myosin IIB was strongly localized to the extensively developed circumferential actin bundles. (F–H) α-18/α-catenin/ZO-1 triple staining in MDCK II cells. The α-18 antibody recognizes a cryptic epitope exposed by the tension-dependent stretching of α-catenin. Weak staining of α-18 along the apical cell junctions was observed. (F′–H′) α-18/α-catenin/ZO-1 triple staining in claudin/JAM-A KO cells. Strong staining of α-18 was observed at the cell–cell junctions, while weak staining was present at the junction breakage sites (asterisk). (I and J) Vinculin/ZO-1 double staining in MDCK II cells. Junctional staining was hardly visible in confluent monolayers. (I′ and J′) Vinculin/ZO-1 double staining in claudin/JAM-A KO cells. Strong accumulation of vinculin was observed at the apical cell junctions, while weak staining was noted at the junction breakage sites (asterisk). Scale bar: 10 μm.