Fig. 2.

Reduced vesicle motility by hypertonicity is a general phenomenon affecting numerous endosome/vesicle subpopulations in various cell types. (A) Endosome/vesicle motility before and after NaCl challenge (500 mOsmol/kg) in LLC-PK₁ cells transfected with various GFP-tagged Rab isoforms (Rab5, -7, -10, and -11) or ssYFP, each used as a marker for specific endosome/vesicle subpopulations as shown in the table at right. The motility of all subpopulations was abolished immediately after challenge, whereas recovery rates varied, as shown in the table at right. (B) Kymographs illustrate different rates of recovery in cells expressing GFP-Rab10, ssYFP, or GFP-Rab11. (C–E) The effects of NaCl challenge on the motility of dextran-loaded endosomes in primary hepatocytes (C), primary pancreatic β cells (D), and cultured pancreatic MIN6 cells (E). (Also see Figs. S1 and S2 and Movies S2 and S3.) Error bars show mean ± SEM from four independent experiments.