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Figure S3. Exit site up-regulation induced by Sar1p binding to T2-GFP involves new and preexisting sites. Means per cell for the number, area, and intensity of above-threshold Sec13 objects are compared at the indicated concentrations for the alanine-substituted peptide (R→A) or the GalNAcT2 cytoplasmic domain peptide (wt). Note that increases in exit site number and size are both specifically inhibited by the GalNAcT2 cytoplasmic domain peptide.