MDCs form through membrane extension intermediates. (A) Super-resolution time-lapse images of Rap-induced MDC formation in yeast cells expressing Tom70-yEGFP. Images were acquired over 120 min. White and yellow arrows mark two different MDCs. Scale bar = 1 µm. See associated Video 8. (B) Super-resolution time-lapse images of ConcA-induced MDC formation in yeast cells expressing Tom70-yEGFP. Images were acquired over 120 min. White arrows mark MDCs. Scale bar = 1 µm. See associated Video 9. (C) Quantification of the initial morphology of Tom70-yEGFP structures during MDC biogenesis after ConcA treatment. n = 59 events from three experiments. (D) Super-resolution time-lapse images of CHX-induced MDC formation in yeast cells expressing Tom70-yEGFP. Images were acquired over 120 min. White arrows mark MDCs. Scale bar = 1 µm. See associated Video 10. (E) Quantification of the initial morphology of Tom70-yEGFP structures during MDC biogenesis after CHX treatment. n = 54 events from three experiments. (F) Representative super-resolution confocal fluorescence microscopy image of a cell with two MDCs with different morphologies. MDCs are marked by white arrows. (G) Representative super-resolution confocal fluorescence microscopy image of an MDC with resolvable layers of Tom70-yEGFP. MDC is marked by the white arrow.