Septins localize to a subset of microtubules in MDCK cells. (A) Maximum intensity projection images of super-resolution confocal microscopy z-series stack of an MDCK cell expressing α-tubulin-GFP (inverted forest green) and mCherry-SEPT9_i1 (inverted magenta). Outlined region (dashed rectangle) is shown in higher magnification. Scale bars, 10 μm (low magnification) and 5 μm (high magnification). (B) Maximum intensity projection images of a super-resolution confocal microscopy z-series stack of an MDCK-mCherry-SEPT9_i1 cell, which was stained for endogenous α-tubulin and SEPT7. An artificial microtubule-SEPT7 overlap channel was created (SEPT7-coated microtubules), showing all α-tubulin fluorescence that colocalizes with SEPT7 (inverted magenta), and the overlay between this channel and mCherry-SEPT9_i1 (inverted forest green) is displayed. Scale bar, 10 μm.