Sara endosomes and the asymmetric division of intestinal stem cells

Montagne, Chrystelle; González‐Gaitán, Marcos

doi:10.1242/jcs.155713

“…Endosomes distribute asymmetrically in polarized cells, which plays important roles in cellular polarization (eg. brush border formation in enterocytes) 40 , in asymmetric cell division 41 , and in maintaining the stemness of pluripotent cells [42][43][44] . Combining multiplexed mRNA and protein readouts with RNA sequencing of organelle fractions and quantitative proteomics [17][18][19]24,45,46 will be instrumental to study the role of subcellular transcript patterning in determining the phenotypic state of single cells and cell collectives, and their ability to display complex patterns of cellular decision making.…”

Section: Csrp1 Levels Negatively Correlate With the Eea1 Protein Levelsmentioning

confidence: 99%

Co-translational targeting of transcripts to endosomes

Popovic

¹

,

Nijenhuis

²

,

Kapitein

³

et al. 2020

Preprint

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Asymmetric localization and translation of mRNAs is used by single cells to sense their environment and integrate extrinsic cues with the appropriate cellular response. Here we investigate the extent to which endosomes impact subcellular patterning of transcripts and provide a platform for localized translation. Using image-based transcriptomics, indirect immunofluorescence, and RNAseq of isolated organelles, we discover mRNAs that associate with early endosomes in a translation-dependent and -independent manner. We explore this in more detail for the mRNA of a major endosomal tethering factor and fusogen, Early Endosomal Antigen 1, EEA1, which localizes to early endosomes in a puromycin-sensitive manner. By reconstituting EEA1 knock-out cells with either the coding sequence or 3UTR of EEA1, we show that the coding region is sufficient for endosomal localization of mRNA. Finally, we use quantitative proteomics to discover proteins associated with EEA1 mRNA and identify CSRP1 as a factor that controls EEA1 translational efficiency. Our findings reveal that multiple transcripts associate with early endosomes in a translation-dependent manner and identify mRNA-binding proteins that may participate in controlling endosome-localized translation.

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“…Interestingly, a recent study has shown that microtubule plus-end motor, Kinesin-I, may be responsible for transport of mRNAs in neurons and polarized epithelial cells 40 . This type of transport would be perfect for targeting mRNAs to the MB, because plus-ends of microtubules are oriented toward the MB, and Kinesin-I has already been implicated in transporting endosomes to the MB during cell division 41 . All these findings hint at a common mechanism that regulates subcellular targeting of mRNAs, although further evidence will be needed to fully determine that.…”

Section: Discussionmentioning

confidence: 99%

The Novel Role of Midbody-Associated mRNAs in Regulating Abscission

Farmer

¹

,

Vaeth

²

,

Han

³

et al. 2022

Preprint

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Midbodies (MBs) have been shown to function during telophase as a recruiting hub, especially for ESCRT-III complex subunits, including CHMP4B, to regulate the abscission step of cytokinesis. However, the molecular machinery governing specific protein targeting and activation at the MB remains poorly understood. Until recently, it was thought that abscission regulating proteins, such as ESCRT-III complex subunits, accumulate at the MB by directly or indirectly binding to the MB resident protein, CEP55. However, recent studies have shown that depletion of CEP55 does not fully block ESCRT-III targeting to the MB, and cells in CEP55 knock-out mice divide normally. Additionally, since MBs are microtubule-rich, proteinaceous structures, it is conceptually hard to imagine how large protein complexes, such as the ESCRT-III complex, can successfully diffuse into the MB from the cytosol in a rapid and highly regulated manner. Here, we show that MBs contain mRNAs and that these MB-associated mRNAs can be locally translated, thus, resulting in the accumulation of abscission-regulating proteins. We also demonstrate that localized MB-associated translation of CHMP4B is required for it’s targeting to the abscission site. Finally, we demonstrate that 3’-UTR-dependent CHMP4B mRNA targeting to the MB is required for successful completion of cytokinesis. Based on all this data, we propose a novel method of regulating cytokinesis and abscission by MB-associated targeting and localized translation of selective mRNAs.

show abstract

“…Interestingly, a recent study has shown that microtubule plus-end motor, Kinesin-I, may be responsible for transport of mRNAs in neurons and polarized epithelial cells 40 . This type of transport would be perfect for targeting mRNAs to the MB, because plus-ends of microtubules are oriented toward the MB, and Kinesin-I has already been implicated in transporting endosomes to the MB during cell division 41 . All these ndings hint at a common mechanism that regulates subcellular targeting of mRNAs, although further evidence will be needed to fully determine that.…”

Section: Discussionmentioning

confidence: 99%

The Novel Role of Midbody-Associated mRNAs in Regulating Abscission

Farmer

¹

,

Han

²

,

Vaeth

³

et al. 2022

Preprint

0

View full text Add to dashboard Cite

Midbodies (MBs) have been shown to function during telophase as a recruiting hub, especially for ESCRT-III complex subunits, including CHMP4B, to regulate the abscission step of cytokinesis. However, the molecular machinery governing specific protein targeting and activation at the MB remains poorly understood. Until recently, it was thought that abscission regulating proteins, such as ESCRT-III complex subunits, accumulate at the MB by directly or indirectly binding to the MB resident protein, CEP55. However, recent studies have shown that depletion of CEP55 does not fully block ESCRT-III targeting to the MB, and cells in CEP55 knock-out mice divide normally. Additionally, since MBs are microtubule-rich, proteinaceous structures, it is conceptually hard to imagine how large protein complexes, such as the ESCRT-III complex, can successfully diffuse into the MB from the cytosol in a rapid and highly regulated manner. Here, we show that MBs contain mRNAs and that these MB-associated mRNAs can be locally translated, thus, resulting in the accumulation of abscission-regulating proteins. We also demonstrate that localized MB-associated translation of CHMP4B is required for it’s targeting to the abscission site. Finally, we demonstrate that 3’-UTR-dependent CHMP4B mRNA targeting to the MB is required for successful completion of cytokinesis. Based on all this data, we propose a novel method of regulating cytokinesis and abscission by MB-associated targeting and localized translation of selective mRNAs.

show abstract

Sara endosomes and the asymmetric division of intestinal stem cells

Cited by 4 publications

References 16 publications

Co-translational targeting of transcripts to endosomes

Co-translational targeting of transcripts to endosomes

The Novel Role of Midbody-Associated mRNAs in Regulating Abscission

The Novel Role of Midbody-Associated mRNAs in Regulating Abscission

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