Figure 2.

TGFβ-treated cells exhibit a slight bias in positioning the Golgi behind the nucleus, whereas untreated cells show an equal tendency to position the Golgi ahead or behind the nucleus. (a) A time series of a TGFβ-treated cell migrating from the bottom (t = 0 min) to the top (137.5 min). The nucleus H2B-GFP) is labeled in green and the Golgi (GM130-RFP) in red. The Golgi position relative to the nucleus (GPRN) shifts from the A to the U to the B state. See Video S1. Scale bars, 50 μm. (b) A schematic of scenarios in which GPRN is scored as being in the Ahead or Behind state. The direction of cell migration at time t is determined from the movement of the nucleus (N, green). In relation to migration direction, if the Golgi (G, red) is ahead of the nucleus (top), GPRN at time t is classified in the A state. If the Golgi is behind the nucleus in relation to migration (bottom), GPRN state is B. The Golgi position is unknown (U) when the cell is not observed to move during the time interval, when the Golgi is not observable, or when the centroids of the Golgi and nucleus coincide along the migration axis. (c) The fraction of time untreated and TGFβ-treated cells spend with the Golgi ahead (open bars) or behind (filled) the nucleus or with the Golgi state unknown (gray) was quantified. Error bars are mean ± standard error, with n = 49 cells (untreated) and n = 61 cells (TGFβ treated) spanning three and six independent trials, respectively. Differences in fraction time spent in A, B, and U states are statistically significant within each treatment group (^∗p < 0.0001) except that the time spent in A versus B for untreated cells is indistinguishable (#p > 0.35), as determined by ANOVA (analysis of variance) followed by post hoc Tukey’s test.