Optogenetic dissection of mitotic spindle positioning in vivo
- Utrecht University, Netherlands
- University of North Carolina at Chapel Hill, United States
Abstract
The position of the mitotic spindle determines the plane of cell cleavage, and thereby daughter cell location, size, and content. Spindle positioning is driven by dynein-mediated pulling forces exerted on astral microtubules, which requires an evolutionarily conserved complex of Gα-GDP, GPR-1/2Pins/LGN, and LIN-5Mud/NuMA proteins. To examine individual functions of the complex components, we developed a genetic strategy for light-controlled localization of endogenous proteins in C. elegans embryos. By replacing Gα and GPR-1/2 with a light-inducible membrane anchor, we demonstrate that Gα-GDP, Gα-GTP, and GPR-1/2 are not required for pulling-force generation. In the absence of Gα and GPR-1/2, cortical recruitment of LIN-5, but not dynein itself, induced high pulling forces. The light-controlled localization of LIN-5 overruled normal cell-cycle and polarity regulation and provided experimental control over the spindle and cell-cleavage plane. Our results define Gα∙GDP-GPR-1/2 Pins/LGN as a regulatable membrane anchor, and LIN-5Mud/NuMA as a potent activator of dynein-dependent spindle-positioning forces.
Data availability
Our design algorithm is accessible via a web interface at http://104.131.81.59/, and the source code can be found at https://github.com/dannyhmg/germline. The data that support the findings of this study are included in the supplementary information. All key plasmids and strains will be deposited with Addgene and the CGC upon publication.
Article and author information
Author details
Lars-Eric Fielmich
Sander Van den Heuvel
Funding
Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO TOP/ECHO grant 711.015.001)
- Lars-Eric Fielmich
- Sander Van den Heuvel
National Institutes of Health (NIH R01 GM083071)
- Bob Goldstein
Helen Hay Whitney Foundation
- Daniel J Dickinson
European Research Council (Synergy grant 609822)
- Ruben Schmidt
- Anna Akhmanova
National Institutes of Health (NIH K99 GM115964)
- Daniel J Dickinson
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2018, Fielmich et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 5,974
- views
-
- 821
- downloads
-
- 71
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Optogenetic dissection of mitotic spindle positioning in vivo
eLife 7:e38198.
https://doi.org/10.7554/eLife.38198
Further reading
-
- Cancer Biology
- Cell Biology
TIPE (TNFAIP8) has been identified as an oncogene and participates in tumor biology. However, how its role in the metabolism of tumor cells during melanoma development remains unclear. Here, we demonstrated that TIPE promoted glycolysis by interacting with pyruvate kinase M2 (PKM2) in melanoma. We found that TIPE-induced PKM2 dimerization, thereby facilitating its translocation from the cytoplasm to the nucleus. TIPE-mediated PKM2 dimerization consequently promoted HIF-1α activation and glycolysis, which contributed to melanoma progression and increased its stemness features. Notably, TIPE specifically phosphorylated PKM2 at Ser 37 in an extracellular signal-regulated kinase (ERK)-dependent manner. Consistently, the expression of TIPE was positively correlated with the levels of PKM2 Ser37 phosphorylation and cancer stem cell (CSC) markers in melanoma tissues from clinical samples and tumor bearing mice. In summary, our findings indicate that the TIPE/PKM2/HIF-1α signaling pathway plays a pivotal role in promoting CSC properties by facilitating the glycolysis, which would provide a promising therapeutic target for melanoma intervention.
-
- Cell Biology
The induction of adipose thermogenesis plays a critical role in maintaining body temperature and improving metabolic homeostasis to combat obesity. β3-adrenoceptor (β3-AR) is widely recognized as a canonical β-adrenergic G-protein-coupled receptor (GPCR) that plays a crucial role in mediating adipose thermogenesis in mice. Nonetheless, the limited expression of β3-AR in human adipocytes restricts its clinical application. The objective of this study was to identify a GPCR that is highly expressed in human adipocytes and to explore its potential involvement in adipose thermogenesis. Our research findings have demonstrated that the adhesion G-protein-coupled receptor A3 (ADGRA3), an orphan GPCR, plays a significant role in adipose thermogenesis through its constitutively active effects. ADGRA3 exhibited high expression levels in human adipocytes and mouse brown fat. Furthermore, the knockdown of Adgra3 resulted in an exacerbated obese phenotype and a reduction in the expression of thermogenic markers in mice. Conversely, Adgra3 overexpression activated the adipose thermogenic program and improved metabolic homeostasis in mice without exogenous ligand. We found that ADGRA3 facilitates the biogenesis of beige human or mouse adipocytes in vitro. Moreover, hesperetin was identified as a potential agonist of ADGRA3, capable of inducing adipocyte browning and ameliorating insulin resistance in mice. In conclusion, our study demonstrated that the overexpression of constitutively active ADGRA3 or the activation of ADGRA3 by hesperetin can induce adipocyte browning by Gs-PKA-CREB axis. These findings indicate that the utilization of hesperetin and the selective overexpression of ADGRA3 in adipose tissue could serve as promising therapeutic strategies in the fight against obesity.
