New signaling kid on the block: the role of the postmitotic midbody in polarity, stemness, and proliferation

Abstract

To complete cytokinesis, abscission of the proteinaceous and microtubule-rich intercellular bridge needs to occur. The midbody (MB), a structure that forms on the intercellular bridge, is a key regulator of cytokinesis and appears to play a role in downstream signaling after abscission. Initially, it was thought that after abscission was completed, the MB was degraded. However, a new body of evidence has emerged suggesting that one daughter cell or a surrounding non–daughter cell can inherit or internalize the MB, thus leading to changes in cell proliferation and differentiation. In this review, we highlight the role that the MB has after mitosis. We will focus on the rising evidence that the MB plays an important role in establishment of cell polarity, such as apical lumen formation, neurite extension, and ciliation. Additionally, we will discuss the evidence suggesting that MBs can also serve the role of signaling organelles (MBsomes) that lead to cell proliferation, differentiation, and even tumorigenicity.

A meiotic midbody structure in mouse oocytes acts as a barrier for nascent translation to ensure developmental competence

“…Studies on MB functions have extended beyond regulatory functions of cytokinesis, and now indicate their signaling capabilities 6 and ribonucleoprotein (RNP) properties [14][15][16] . An array of proteins involved in translation, translational regulation, and RNA molecules are enriched in mitotic MBs.…”

“…In somatic cells, the final stage of MB formation is abscission, or severing, of the microtubule arms, which leads to the extracellular release of the membrane-bound organelle (MBR) 24 . After release, the MBR can be internalized through phagocytosis, now called a MBsome, a necessary step for its regulatory functions 6,24 . Because we observed several asymmetries at the subcellular level in oocyte mMBs, we hypothesized that abscission of mMBs is asymmetric and is retained in the egg.…”

“…1a), enabling neighboring cells to phagocytose them [3][4][5] . These MB remnants (MBRs), when phagocytosed by cancer and stem cells, are correlated with regulation of tumorigenicity and stemness, respectively, suggesting that MBR uptake has cell type-specific effects 6 . Mammalian oocytes, which undergo asymmetric divisions, could have either an asymmetric abscission and inheritance of the MBR, or a symmetric abscission as observed in somatic cells (Fig.…”

The Novel Role of Midbody-Associated mRNAs in Regulating Abscission

“…Furthermore, recent studies have also shown that during cell division MBs can be released in the extracellular milieu where they are called MBsomes of Flemmingsomes 8, 23 . Uptake of these MBsomes by other cells can lead to changes in cell fate, differentiation, and proliferation capacity, presumably by mediating lateral transfer of specific signaling molecules 23, 24, 34 . However, what remains unclear is what these signaling molecules are and how they may affect cells after MBsome internalization.…”

The Novel Role of Midbody-Associated mRNAs in Regulating Abscission

“…Furthermore, recent studies have also shown that during cell division MBs can be released in the extracellular milieu where they are called MBsomes of Flemmingsomes 8,23 . Uptake of these MBsomes by other cells can lead to changes in cell fate, differentiation, and proliferation capacity, presumably by mediating lateral transfer of speci c signaling molecules 23,24,34 . However, what remains unclear is what these signaling molecules are and how they may affect cells after MBsome internalization.…”