The accurate segregation of organelles during cell division is crucial for proper cell duplication and survival. This is especially complex for those organelles that cannot be generated de novo and are interlinked by membrane contact sites, such as mitochondria, peroxisomes and the endoplasmic reticulum (ER), and it is not well understood how these intricate networks are preserved in the daughter cell. In this Short Report, David Drubin and colleagues (Li et al., 2021) use time-lapse imaging to simultaneously track five organelles during mitosis in the budding yeast Saccharomyces cerevisiae to investigate how their inheritance is coordinated. They observe a preferred succession of organelles into the growing bud, which occurs in three stages. Cortical ER and peroxisomes are inherited first during bud emergence, followed by that of the vacuole and mitochondria into small buds. Finally, the nucleus and nuclear ER are inherited when the bud has nearly reached its final size. The authors then address whether organelle inheritance is coordinated with the cell cycle, but surprisingly, cell cycle disruption does not affect organelle inheritance or its sequential progression. When cells are arrested in S-phase specifically, the order of the three stages is retained, but the nucleus is not inherited. Taken together, these findings point to an ordered inheritance of organelles, whose temporal sequence is independent of cell cycle progression.
