The Crosstalk Between Morphological Changes of Subcellular Organelles and Mitosis/Meiosis: Molecular Mechanisms and Beyond

Mitosis and meiosis are the key steps in ensuring the faithful inheritance of genetic material. During these processes, the chromosomes condense, align on the central plate and segregate. However, mitosis and meiosis are more than just chromosome segregation. Since subcellular organelles can't be replicated de novo, they have to undergo significant morphological changes to ensure their faithful distribution into daughter cells after cell division. For example, mitochondria change from a tubular network at interphase into individual puncta after entering mitosis. In order to induce mitochondrial fragmentation, the mitotic kinase CDK1 phosphorylates GTPase DRP1 to promote its targeting on mitochondria as well as fission activity. Other mitotic kinases, such as Aurora A, are also required for proper DRP1 activity. This indicates that the morphological change of mitochondria and mitosis are closely related.

In recent years, several studies have found that morphological changes of organelles also affect the cell cycle. DRP1 depletion causes mitochondrial fission defects and decreases cyclin E expression. Depletion of MFF, recruiter of DRP1 on mitochondria, results in the mis-alignment of mitotic chromosomes. In fact, fragmented mitochondria in mitotic cells associate with spindle microtubes to move towards the end of spindle and this transportation is mediated by the Rho GTPase Miro. Miro also regulates the ER and mitochondria contact sites, where mitochondrial fission happens, and recruits the outer kinetochore protein CENP-F to mitochondria at the time of cytokinesis. Therefore, mitochondrial morphological changes and transportation are tightly linked to mitotic progress.

In this Research Topic, we focus on the crosstalk between subcellular organelles and the mitotic/meiotic spindle and chromosomes. We are particularly interested in understanding how mitotic and meiotic kinases regulate morphological changes of mitochondria/ER/Golgi body and how these morphology changes affect mitotic and meiotic progress at the cellular and molecular level. The ultimate goal is to uncover how morphological changes of organelles and mitotic and meiotic progression are linked.

The specific themes for this Research Topic include, but are not limited to the following:
• Mitotic/meiotic kinases that are essential for the morphological changes of mitochondria/ER/Golgi body and the underlying molecular mechanisms.
• New proteins on mitochondria/ER/Golgi body that can affect mitosis/meiosis
• The signaling pathways affecting both subcellular organelle morphology and mitosis/meiosis
• New strategies of imaging and quantifying cellular morphology changes and spindle formation defects.
• Studies uncovering defects in (sub)cellular organelle morphology changes in disease states.
• Reviews that comprehensively cover the most recent progress within this topic.