VAMP7 knockdown and overexpression alters lysosome volume.

<p>MDCK cells were transfected with cDNA encoding GFP-VAMP7 (A) or with control or VAMP7 siRNA (B) and processed for immunofluorescence to detect LAMP2 after four days. (C) Percent change +/− standard error of the mean in lysosome volume normalized to its respective control was quantitated using Imaris software as described in Methods. Compared to cells transfected with control siRNA, cells treated with VAMP7 siRNA had smaller LAMP2-positive structures compared to control. In contrast, VAMP7 overexpression (OE) led to an enlargement of LAMP2-positive structures. A total of ten stacks in two experiments were quantitated Scale bars = 10 µm; (* p<0.01 using two-sample t-test; **p<0.001 using paired t-test; see Methods for details.).