Septal localization of the membrane-bound division proteins of Bacillus subtilis DivIB and DivIC is codependent only at high temperatures and requires FtsZ

Using immunofluorescence microscopy, we have examined the dependency of loc alization among three Bacillus subtilis division proteins, FtsZ, DivIB, and DivIC, to the division site. DivIC is required for DivIB localization. How ever, DivIC localization is dependent on DivIB only at high growth temperat ures, at which DivIB is essential for division. FtsZ localization is requir ed for septal recruitment of DivIB and DivIC, but FtsZ can be recruited ind ependently of DivIB. These localization studies suggest a more specific rol e for DivIB in division, involving interaction with DivIC.