Figure 2.

MTs parallel to the cell edge in β cells are destabilized in high glucose. (A and B) Examples of MT directionality quantification in low (A) and high (B) glucose are shown. Tubulin, green. Insulin (β cell marker), magenta. Cell outline, as detected by E-cadherin staining, is shown as a dotted line on tubulin and thresholded images. The image on the right shows color-coded MT directions: parallel to the cell edge, blue; perpendicular to the cell edge, red. (C and D) Histograms of MT directionality within two cell regions are shown: periphery (C) and interior (D). Percentage of tubulin-positive pixels in the analyzed cell population is shown. MTs at the periphery tend to be parallel to the edge. Low and high glucose do not differ. Bars indicate averages over N = 12 and 11 cells for low and high glucose, respectively, and error bars indicate standard deviations. Pixel numbers in the analysis: 71,759 (low, periphery); 9622 (low, interior); 43,747 (high, periphery); 5833 (high, interior). Note that a lower number of pixels were identified in high glucose, consistent with the fact that MTs are destabilized under this condition. (E and F) Stable MT marker detyrosinated (Glu-)tubulin (green) in low (E) and high (F) glucose is shown. Cell-cell adhesions are stained for E-cadherin (magenta) in left-hand panels and outlined (dashed line) in right-hand panels. Note multiple Glu-tubulin-positive MTs parallel to the cell border (arrows) in low glucose (E). Glu-tubulin content is decreased in high glucose (F), indicating MT destabilization both across the cell and at the cell border (arrows). To see this figure in color, go online.