Reduced levels of ubiquitinatable Ist1 are sufficient for recycling. (A) Schematic showing YETI system to regulate levels of IST1 expression. (B and C) Immunoblot depicting Ist1 levels from YETI-IST1 cells exposed to indicated β-estradiol titrations with concentrations used to mimic Ist1^WT (green) and Ist1^KR (pink) levels estimated with SD (n = 3) shown. (D) Airyscan microscopy of Mup1-GFP expressed in YETI-IST1 cells exposed to β-estradiol concentrations required to mimic ist1∆, Ist1^WT, and Ist1^KR levels for 6 h prior to imaging. (E) FM4-64 efflux measurements from WT cells and YETI-IST1 cells exposed to β-estradiol to mimic Ist1^WT and Ist1^KR levels prior to loading with dye for 8 min at RT. Scale bar, 5 μm. Source data are available for this figure: SourceData F8.