Distinct Dynamics of Endocytic Clathrin-Coated Pits and Coated Plaques (original) (raw)
Figure 4
Increase of cell motility correlates with loss of plaques.
(A) Expression in U373 astrocytes of EGFP-LCb-EED/QQN prevents plaque formation. U373 astrocytes were transfected with EGFP-LCb-EED/QQN or with EGFP-LCb as control, and their clathrin structures imaged 48 h after transfection. The semilogarithmic plots represent maximum fluorescence versus time of pits and plaques from two cells expressing similar amounts of EGFP-LCb or EGFP-LCb-EED/QQN. The average lifetimes are 69±23 s (n = 129) for canonical pits tagged with EGFP-LCb is and 232±78 s (n = 30) for plaques; the corresponding fluorescence intensity maxima are 1,420±536 and 2,087±455, respectively. The difference in maximum fluorescence intensity is statistically significant (p<0.0001). The right panels are snapshots from two different time points of a video acquired from cells expressing EGFP-LCb-EED/QQN using the WF fluorescence combined with bright-field phase illumination; the images show the elongated shape of the cells and the change in their position. Control cells (unpublished data) are more symmetric and remain stationary. (B) Increased motility of cells correlates with absence of plaques. Each panel shows four motility tracks, each from a different cell that either expresses its endogenous clathrin light chains (not transfected), or where they have been replaced, by overexpression, with EGFP-LCb or EGFP-LCb-EED/QQN.