COS 7 cell expressing Organelle LightsTM ER-GFP (Invitrogen) consisting of the signal sequence of the ER protein calreticulin and a KDEL retention sequence. Images were collected with a 63X 1.4 NA Plan-Apochromat oil objective on a Zeiss LSM510 META (Carl Zeiss,Thornwood, NY) using 488 nm excitation, HFT 488 dichroic, and LP505emission filter. Image size is 1024 x 1024, pixel size is 0.07 µm x 0.07 µm and pixel time was set to 1.28 µsec. Detector pinhole was set to collect 25 ~0.5 µm slices at 0.5 µm intervals.