Cell Biology

eLife assessment

These authors present a powerful tool to unbiasedly identify lysosome-associated proteins in C. elegans, and they provide a compelling, in-depth assessment of how this method can be used to understand longevity pathways and identify novel proteins. Understanding lysosomal differences in specific tissues or in response to different longevity conditions are exciting as it provides new insight into how organelles could control specific homeostasis responses. This valuable tool and proteomics datasets also represent a great resource for the C. elegans community and should pry open new studies on the regulation and role of the lysosome at the organismal level.

eLife assessment

In this study, the authors present important tools for monitoring distinct tissue-specific patterns of agonist-induced Free Fatty Acid receptor 2 phosphorylation. The work includes several validation experiments, which provide convincing evidence that will be beneficial for the scientific community.

eLife assessment

This study defines the roles for two different missense mutations observed in patients in the Trabid/ZRANB1 gene associated in children with a range of congenital disorders including reduced brain size. The study is important because the findings have theoretical or practical implications beyond a single subfield, as the study of DUB and cytoskeletal alterations have implications for neurodevelopment broadly. The methods are convincing as they utilize appropriate and validated methodology in line with current state-of-the-art by incorporating knock-in mice of the patient mutations. Many of the reviewer comments were focused on potential next experiments, rather than on evaluation of the data at hand, and the authors have considered these as future studies. The work as presented suggests critical roles for Trabid in the STRIPAK complex mediating APC deubiquitylation.

eLife assessment

This manuscript is an important advance in the study of Histone H1s, finding distinct distributions of various H1 variants in the genome. The controls presented by the authors provide convincing evidence to demonstrate a heterogenous distribution of H1 which might reflect functional regulation of chromatin accessibility by linker histones. This work will be of interest to the genome organization field, and could additionally provide a framework for understanding H1 mis-regulation observed in cancer cells.

eLife assessment

This paper investigates the potential role of extracellular vesicles in providing extracellular matrix signals for migration of vascular smooth muscle cells. The findings could be useful for researchers interested in cell migration, but the evidence supporting the conclusions is presently incomplete.

eLife assessment

This valuable manuscript systematically addresses the role of intracellular lipid transfer proteins on cellular lipid levels. The authors have provided solid evidence on the role of ORP9 and ORP11 in sphingolipid metabolism at the Golgi complex. The data is in general convincing, except for the claim that ORP9/11 might counter-exchange phosphatidylinositol 4-phosphate and phosphatidylserine, which is not fully supported by the data presented. This article will be of broad interest to cell biologists interested in lipid metabolism and membrane biology.

eLife assessment

This fundamental study advances our understanding of TRAIL-induced apoptosis by defining how Heparan triggers this pathway at the molecular level. The evidence supporting the conclusions is compelling, with rigorous binding assays, structural methods, and cellular studies. The work will be of broad interest to cell biologists and biochemists.

eLife assessment

These solid results demonstrate that arpin is expressed in the endothelium of blood vessels and its deficiency leads to leaky blood vessels in in vivo and in vitro models, although the work does not clarify the mechanistic connection between arpin and increased ROCK activity. The study adds some insights to our understanding of the complicated network of proteins that control this process, and it will be useful to individuals within this defined field of study.

eLife assessment

The authors report useful findings on novel function of apical ICAM1 in regulating bile duct homeostasis in the liver. The strength of evidence is solid using appropriate methodolgy with only minor weakness. The findings will be of interest to researchers in hepatology and membrane traffic biology.

eLife assessment

This is a solid methods paper developing a machine learning based protocol differentiating normal and diseased myofibers. It emerges with and validates a potentially valuable approach to diifferentiate healthy and Duchenne muscle dystrophy myofibers.

eLife assessment

Chen and colleagues utilize an in situ explant model of the neural retina and retinal pigment epithelium (RPE), along with small molecule inhibition of key metabolic enzymes and targeted metabolomic analysis, to decipher key differences in metabolic pathways used by rods, cones, Muller glia, and the RPE. They conclude that rods are heavily reliant on oxidative metabolism, cones are heavily reliant on glycolysis, and multiple mechanisms exist to decouple glycolysis from oxidative metabolism in the retina. This study provides valuable metabolomic data and insights into the metabolic flexibility of different retinal cells. However, current evidence is still incomplete as several of the conclusions from the paper stand in contradiction to other published findings and the authors naturally suggests experiments that will be needed in the future to validate the hypothesized pathways and refute existing published data. Such future validation includes animal models with tissue specific knockout of the key enzymes probed in the study; inhibiting the targets of this study with more than 1 small molecule that is structurally different, and at different doses and timings; using retinal explants from matured animals; performing labeled metabolite tracing experiments; and direct assessment of mitochondrial function (via OCR) under various manipulations.

eLife assessment

This valuable study reports on the packing of molecules in cellular compartments, such as actin-based protrusions. The study provides solid evidence for parameters that enable the building of a biophysical model of filopodia, which is required to gain a complete understanding of these actin-based structures. Some areas of the manuscript require further clarification.

eLife assessment

This important study combines a range of advanced ultrastructural imaging approaches to define the unusual endosomal system of African trypanosomes. Compelling images reveal that, unlike a conventional set of compartments, the endosome in these protists forms a continuous membrane system with functionally distinct subdomains, as defined by canonical markers for early, late, and recycling endosomes. The findings compellingly support that the endocytic system in bloodstream stages has adapted to support remarkably high rates of membrane turnover necessary for immune complex removal and survival in the blood. This research is particularly relevant to those investigating infectious diseases

eLife assessment

This fundamental study significantly advances our understanding of the role of water influx and swelling on neutrophil migration in response to chemoattractant. The evidence supporting the conclusions, based on a genome-wide CRISPR screen and high quality cellular observations, is compelling. This paper will be of interest to cell biologists and biophysicists working on cell migration.

eLife assessment

This study presents valuable new insights from the protist Tetrahymena regarding radial spokes, conserved protein complexes that are important for cilia motility. The work employs interdisciplinary approaches to provide convincing support for radial spoke composition with some experiments, but there are weaker areas with partially incomplete support, such as relying on knockouts alone rather than including localization studies of tagged proteins.

eLife assessment

In this study, Sparta et al., generated and employed a battery of fluorescent reporters that allowed them to perform time-resolved monitoring of mechanistic target of rapamycin complex 1 (mTORC1) responses to stimuli including glucose, amino acids, and insulin at the single cell resolution. The results of this elegant approach support a model of graded mTORC1 activation in response to the aforementioned stimuli when applied individually or in combination. This model is consistent with continuous adjustment of mTORC1 signaling to changes in cellular environment and opposed to the "on/off" model of mTORC1 function. Considering the pivotal role of mTORC1 in integrating signals such as nutrients, hormones, growth factors, oxygen, and energy status with a plethora of outputs that affect cell fate and organismal physiology, it was thought that this study will be of interests across a variety of biomedical disciplines. Overall, the elegance and robustness of the approach was highly appreciated, though the paper would be strengthened by addressing some technical issues and concerns regarding the positioning of the proposed model of mTORC1 regulation in the field.

eLife assessment

This valuable study presents a solid transcriptomic analysis of enterochromaffin cells, but there are weaknesses in the functional and physiological data describing the role of enterochromaffin cell mechanosensory receptors (Piezo2 channels) in regulating colonic motility.

eLife assessment

This important study reports a new mutant mouse line with compromised function of a DNA damage response protein. The evidence supporting the conclusion that the mutants display defective maintenance of meiotic sex chromosome inactivation is solid. This work is of interest to biomedical researchers working on meiosis and meiotic sex chromosome inactivation.

eLife assessment

The manuscript by Kahraman et al. describes the use of a fluorescent dye for purifying and analyzing human islet alpha cells. The study provides solid evidence that the alpha cells can be purified using this method and the cells remained viable and functional after culturing for several days. The significance of the study is access to a new tool that will be useful for islet biologists and researchers studying diabetes mechanisms.

eLife assessment

This important study identifies a short amino acid sequence that, when fused in multimeric form to the amino termini of luminal ER proteins, initiates proteasomal degradation via the Hrd1 ER quality control ubiquitin ligase complex. The authors provide solid evidence that this sequence functions as a "degron" for ER proteins. Future work is required to get a more detailed view of the properties of this degron, the mechanisms underlying its recognition by ER-resident and cytoplasmic factors, and the in vivo relevance of the findings.