Cell Biology

Tracking maternal proteins uncovers a central role for the residual body in organelle recycling during Toxoplasma gondii replication

1. Julia von Knoerzer-Suckow
2. Parnian Sazegar
3. Javier Periz
4. Simon Gras
5. Markus Meissner

• Curated by eLife

  eLife Assessment

  This study presents valuable new insights into the patterns of organelle inheritance in the protozoan parasite Toxoplasma gondii. An innovative dual-labeling approach used in this study to track maternal-derived and de novo synthesized organelles provides a technical advance with potential to be more broadly applied. Solid evidence is provided that different organelles show distinct inheritance fates during cell replication; however, the data describing the residual body component in this process is incomplete.

Reviewed by eLife

When mitochondria fall apart: Unbalanced mitochondrial segregation triggers loss of mtDNA in the absence of mitochondrial fusion

1. Lisa Dengler
2. Francesco Padovani
3. Bianca Lemke
4. Rebecca Brugger
5. Benedikt Westermann
6. Boris Maček
7. Kurt M. Schmoller
8. Jennifer C. Ewald

Reviewed by Review Commons

MORC2 Mediates Transcriptional Regulation Through Liquid-Liquid Phase Separation and DNA Binding

1. Yanshen Zhang
2. Weiya Xu
3. Wenxiu Duan
4. Yu Wei
5. Wenli Jiang
6. Feng Zhu
7. Chengdong Huang
8. Chao Wang
9. Yihui Bi

• Curated by eLife

  eLife Assessment

  This useful study has demonstrated that MORC2 undergoes phase separation in cells and established multiple interactions responsible for the phase separation. While the characterizations of protein-protein and protein-DNA interactions are solid, there is currently incomplete evidence supporting the claim that MORC2 phase separation contributes to the gene regulatory role of MORC2 in cells. With a stronger link between MORC2 phase separation and cellular function, and further analysis of how disease-linked mutations impact condensation propensity, this study would be of significant interest to biophysicists and molecular biologists working on the role of condensates in gene regulation.

Reviewed by eLife

A GCN1-independent activator of the kinase GCN2

1. JiaYi Zhu
2. Giulia Emanuelli
3. Glenn R Masson
4. Vanesa Vinciauskaite
5. Henriette Willems
6. Andrew Lim
7. Christopher Alan Brown
8. David Winpenny
9. Murray Clarke
10. Rebecca Gilley
11. Fergus Preston
12. Jordan Wilson
13. Aldo Bader
14. Taufiq Rahman
15. Joseph E Chambers
16. John Skidmore
17. Nicholas W Morrell
18. Stefan J Marciniak

• Curated by eLife

  eLife Assessment

  This study presents a screen for small-molecule activators of the kinase GCN2 that phosphorylates the eukaryotic translation initiation factor 2 alpha (eIF2α) in response to diverse stress stimuli. Among the compounds identified, one stands out as a potent activator that functions independently of GCN1, which is important for probing mechanisms of Integrated Stress Response regulation and may have translational relevance in the context of pathogenic GCN2 mutations. While some reviewers found the biochemical analyses convincing, others viewed the cellular evidence as limited, particularly with respect to time points, endogenous readouts, and broader cell-type validation, which prevents a clear assessment of the compound's potential potency in a physiological context.

Reviewed by eLife

Identification of nuclear pore proteins at plasmodesmata: potential role in intercellular transport?

1. T Moritz Schladt
2. Manuel Miras
3. Jona Obinna Ejike
4. Mathieu Pottier
5. Lin Xi
6. Andrea Restrepo-Escobar
7. Masayoshi Nakamura
8. Niklas Pütz
9. Sebastian Hänsch
10. Chen Gao
11. Julia Engelhorn
12. Marcel Dickmanns
13. Gwendolyn V Davis
14. Ahan Dalal
15. Sven Gombos
16. Ronja Lange
17. Rüdiger Simon
18. Waltraud X Schulze
19. Wolf B Frommer

• Curated by eLife

  eLife Assessment

  Plasmodesmata are channels that allow cell-cell communication in plants; based on the functional similarities between facilitated transport within plasmodesmata and into the nucleus, the authors speculate that nuclear pore complex proteins might be involved in plasmodesmata function. If supported, this would transform our understanding of cell-to-cell communication in plants. The authors localize nuclear pore complex proteins to plasmodesmata using proteomics and heterologous overexpression; however, the data are incomplete since key controls for localization, functionality, and expression level of fluorescent protein fusions are absent.

Reviewed by eLife

The fate of pyruvate dictates cell growth by modulating cellular redox potential

1. Ashish G Toshniwal
2. Geanette Lam
3. Alex J Bott
4. Ahmad A Cluntun
5. Rachel Skabelund
6. Hyuck-Jin Nam
7. Dona R Wisidagama
8. Carl S Thummel
9. Jared Rutter

• Curated by eLife

  eLife Assessment

  This fundamental work demonstrates that compartmentalized cellular metabolism is a dominant input into cell size control in a variety of mammalian cell types and in Drosophila. The authors show that increased pyruvate import into the mitochondria in liver-like cells and in primary hepatocytes drives gluconeogenesis but reduces cellular amino acid production, suppressing protein synthesis. The evidence supporting the conclusions is compelling, with a variety of genetic and pharmacologic assays rigorously testing each step of the proposed mechanism. This work will be of interest to cell biologists, physiologists, and researchers interested in cell metabolism, and is significant because stem cells and many cancers exhibit metabolic rewiring of pyruvate metabolism.

Reviewed by eLife

Lipid packing contributes to the confinement of caveolae to the plasma membrane

1. Elin Larsson
2. Aleksei Kabedev
3. Hudson Pace
4. Jakob Lindwall
5. Fouzia Bano
6. Robert G Parton
7. Christel AS Bergström
8. Ingela Parmryd
9. Marta Bally
10. Richard Lundmark

• Curated by eLife

  eLife Assessment

  This study reports the important finding that the dynamin inhibitor Dyngo-4a broadly affects lipid packing and plasma membrane dynamics, independently of its action on dynamin. While solid computational, biophysical, and cell-based evidence supports this conclusion, there is incomplete support for the authors' main claim on the role of lipid packing in caveolae internalization, as the causal relationship remains unclear and direct analyses are lacking. With stronger evidence, this work would be of significant interest to cell biologists, biophysicists, and chemists interested in membrane remodeling and drug-membrane interactions.

  [Editors' note: this paper was reviewed by Review Commons.]

Reviewed by eLife, Review Commons

Targeting RhoA activity rejuvenates aged hematopoietic stem cells

1. Eva Mejía-Ramírez
2. Pablo Iañez Picazo
3. Barbara Walter
4. Sara Montserrat-Vazquez
5. Francesco Affuso
6. Stefan Wieser
7. Fabio Pezzano
8. Loïc Reymond
9. Jorge Castillo-Robles
10. Francesca Matteini
11. Loris Mularoni
12. Dídac Maciá
13. Ángel Raya
14. Verena Ruprecht
15. Yi Zheng
16. Paula Petrone
17. M. Carolina Florian

Reviewed by preLights

The Rab7-Epg5 and Rab39-ema modules cooperatively position autophagosomes for efficient lysosomal fusions

1. Attila Boda
2. Villő Balázs
3. Anikó Nagy
4. Dávid Hargitai
5. Mónika Lippai
6. Zsófia Simon-Vecsei
7. Márton Molnár
8. Fanni Fürstenhoffer
9. Gábor Juhász
10. Péter Lőrincz

• Curated by eLife

  eLife Assessment

  This paper presents valuable findings on how autophagosomes are positioned along microtubules for their efficient fusion with lysosomes, providing significant insights into the mechanism. The evidence supporting the conclusions is solid, with high-quality fluorescence microscopy combined with Drosophila genetics. This work will be of broad interest to cell biologists interested in autophagy and related cell biology fields.

Reviewed by eLife

Calcium transfer from the ER to other organelles for optimal signaling in Toxoplasma gondii

1. Zhu-Hong Li
2. Beejan Asady
3. Le Chang
4. Myriam Andrea Hortua Triana
5. Catherine Li
6. Isabelle Coppens
7. Silvia NJ Moreno

• Curated by eLife

  eLife Assessment

  This important study shows that calcium stores in the endoplasmic reticulum of the parasitic protozoan, Toxoplasma gondii play a major role in buffering calcium levels in the cytosol as well as other organelles such as the mitochondrion. Advanced imaging techniques, including use of genetically encoded calcium indicators provide compelling evidence for the role of the SERCA-Ca2+ ATPase pump in regulating organellar calcium levels. However, it remains unclear whether intra-organellar calcium transport occurs via ER-mitochondria membrane contact sites or other mechanisms. This work will be of interest to cell and molecular biologists interested in calcium signalling in divergent eukaryotes.

Reviewed by eLife