scholarly journals ER membrane puts up barriers in C. elegans

2016 ◽  
Vol 214 (6) ◽  
pp. 637-637
Author(s):  
Mitch Leslie
Keyword(s):  
C Elegans ◽  
Fate Determinants ◽  
Er Membrane

Compartmentalization of ER membrane might ensure that fate determinants end up in different cells of embryo.

scholarly journals Compartmentalization of the endoplasmic reticulum in the early C. elegans embryos

2016 ◽  
Vol 214 (6) ◽  
pp. 665-676 ◽  
Author(s):  
Zuo Yen Lee ◽  
Manoël Prouteau ◽  
Monica Gotta ◽  
Yves Barral
Keyword(s):  
Endoplasmic Reticulum ◽  
Cleavage Plane ◽  
Morphological Transition ◽  
Dependent Manner ◽  
Cell Lineages ◽  
C Elegans ◽  
Nuclear Envelope Breakdown ◽  
The One ◽  
Fate Determinants ◽  
Er Membrane

The one-cell Caenorhabditis elegans embryo is polarized to partition fate determinants between the cell lineages generated during its first division. Using fluorescence loss in photobleaching, we find that the endoplasmic reticulum (ER) of the C. elegans embryo is physically continuous throughout the cell, but its membrane is compartmentalized shortly before nuclear envelope breakdown into an anterior and a posterior domain, indicating that a diffusion barrier forms in the ER membrane between these two domains. Using mutants with disorganized ER, we show that ER compartmentalization is independent of the morphological transition that the ER undergoes in mitosis. In contrast, compartmentalization takes place at the position of the future cleavage plane in a par-3–dependent manner. Together, our data indicate that the ER membrane is compartmentalized in cells as diverse as budding yeast, mouse neural stem cells, and the early C. elegans embryo.

scholarly journals Stress sensor Ire1 deploys a divergent transcriptional program in response to lipid bilayer stress

2020 ◽  
Vol 219 (7) ◽  
Author(s):  
Nurulain Ho ◽  
Wei Sheng Yap ◽  
Jiaming Xu ◽  
Haoxi Wu ◽  
Jhee Hong Koh ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Stress Responses ◽  
Metabolic Diseases ◽  
Membrane Integrity ◽  
Membrane Lipid ◽  
Compensatory Response ◽  
C Elegans ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Er Membrane

Membrane integrity at the endoplasmic reticulum (ER) is tightly regulated, and its disturbance is implicated in metabolic diseases. Using an engineered sensor that activates the unfolded protein response (UPR) exclusively when normal ER membrane lipid composition is compromised, we identified pathways beyond lipid metabolism that are necessary to maintain ER integrity in yeast and in C. elegans. To systematically validate yeast mutants that disrupt ER membrane homeostasis, we identified a lipid bilayer stress (LBS) sensor in the UPR transducer protein Ire1, located at the interface of the amphipathic and transmembrane helices. Furthermore, transcriptome and chromatin immunoprecipitation analyses pinpoint the UPR as a broad-spectrum compensatory response wherein LBS and proteotoxic stress deploy divergent transcriptional UPR programs. Together, these findings reveal the UPR program as the sum of two independent stress responses, an insight that could be exploited for future therapeutic intervention.

scholarly journals The Nesprin-1/-2 ortholog ANC-1 regulates organelle positioning in C. elegans without its KASH or actin-binding domains

2020 ◽  
Author(s):  
Hongyan Hao ◽  
Shilpi Kalra ◽  
Laura E. Jameson ◽  
Leslie A. Guerrero ◽  
Natalie E. Cain ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Nuclear Membrane ◽  
Actin Binding ◽  
Nuclear Positioning ◽  
Outer Nuclear Membrane ◽  
Calponin Homology ◽  
C Elegans ◽  
Binding Domains ◽  
Null Phenotype ◽  
Er Membrane

AbstractKASH proteins in the outer nuclear membrane comprise the cytoplasmic half of LINC complexes that connect nuclei to the cytoskeleton. Caenorhabditis elegans ANC-1, an ortholog of Nesprin-1/2, contains actin-binding and KASH domains at opposite ends of a long spectrin-like region. Deletion of either the KASH or calponin homology (CH) domains does not completely disrupt nuclear positioning, suggesting neither KASH nor CH domains are essential. Deletions in the spectrin-like region of ANC-1 led to significant defects, but only recapitulated the null phenotype in combination with mutations in the trans-membrane span. In anc-1 mutants, the ER was unanchored, moving throughout the cytoplasm, and often fragmented. The data presented here support a cytoplasmic integrity model where ANC-1 localizes to the ER membrane and extends into the cytoplasm to position nuclei, ER, mitochondria, and likely other organelles in place.

The expression of the C. elegans labial-like Hox gene ceh-13 during early embryogenesis relies on cell fate and on anteroposterior cell polarity

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4193-4200 ◽  
Author(s):  
C. Wittmann ◽  
O. Bossinger ◽  
B. Goldstein ◽  
M. Fleischmann ◽  
R. Kohler ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Polarity ◽  
Hox Genes ◽  
Positional Information ◽  
Precursor Cell ◽  
Body Parts ◽  
Hox Gene ◽  
C Elegans ◽  
Fate Determinants ◽  
Cell Fate Determinants

Clusters of homeobox-containing HOM-C/hox genes determine the morphology of animal body plans and body parts and are thought to mediate positional information. Here, we describe the onset of embryonic expression of ceh-13, the Caenorhabditis elegans orthologue of the Drosophila labial gene, which is the earliest gene of the C. elegans Hox gene cluster to be activated in C. elegans development. At the beginning of gastrulation, ceh-13 is asymmetrically expressed in posterior daughters of anteroposterior divisions, first in the posterior daughter of the intestinal precursor cell E and then in all posterior daughters of the AB descendants ABxxx. In this paper, we present evidence that supports position-independent activation of ceh-13 during early C. elegans embryogenesis, which integrates cell fate determinants and cell polarity cues. Our findings imply that mechanisms other than cell-extrinsic anteroposterior positional signals play an important role in the activation and regulation of the C. elegans Hox gene ceh-13.

The Caenorhabditis elegans polarity gene ooc-5 encodes a Torsin-related protein of the AAA ATPase superfamily

Development ◽  
2001 ◽  
Vol 128 (22) ◽  
pp. 4645-4656 ◽  
Author(s):  
Stephen E. Basham ◽  
Lesilee S. Rose
Keyword(s):  
Cell Fate ◽  
Protein Complexes ◽  
Sequence Similarity ◽  
Normal Function ◽  
Par Proteins ◽  
Torsion Dystonia ◽  
Aaa Atpase ◽  
C Elegans ◽  
Fate Determinants ◽  
Cell Fate Determinants

The PAR proteins are required for polarity and asymmetric localization of cell fate determinants in C. elegans embryos. In addition, several of the PAR proteins are conserved and localized asymmetrically in polarized cells in Drosophila, Xenopus and mammals. We have previously shown that ooc-5 and ooc-3 mutations result in defects in spindle orientation and polarity in early C. elegans embryos. In particular, mutations in these genes affect the re-establishment of PAR protein asymmetry in the P1 cell of two-cell embryos. We now report that ooc-5 encodes a putative ATPase of the Clp/Hsp100 and AAA superfamilies of proteins, with highest sequence similarity to Torsin proteins; the gene for human Torsin A is mutated in individuals with early-onset torsion dystonia, a neuromuscular disease. Although Clp/Hsp100 and AAA family proteins have roles in diverse cellular activities, many are involved in the assembly or disassembly of proteins or protein complexes; thus, OOC-5 may function as a chaperone. OOC-5 protein co-localizes with a marker of the endoplasmic reticulum in all blastomeres of the early C. elegans embryo, in a pattern indistinguishable from that of OOC-3 protein. Furthermore, OOC-5 localization depends on the normal function of the ooc-3 gene. These results suggest that OOC-3 and OOC-5 function in the secretion of proteins required for the localization of PAR proteins in the P1 cell, and may have implications for the study of torsion dystonia.

scholarly journals Binary decision between asymmetric and symmetric cell division is defined by the balance of PAR proteins in C. elegans embryos

2020 ◽  
Author(s):  
Yen Wei Lim ◽  
Fu-Lai Wen ◽  
Prabhat Shankar ◽  
Tatsuo Shibata ◽  
Fumio Motegi
Keyword(s):  
Cell Division ◽  
Binary Choice ◽  
Cell Stage ◽  
Par Proteins ◽  
Binary Decision ◽  
C Elegans ◽  
Show Evidence ◽  
Differentiation And Proliferation ◽  
Fate Determinants ◽  
Sister Cells

ABSTRACTCoordination between cell differentiation and proliferation during development requires the balance between asymmetric and symmetric modes of cell division. However, the cellular intrinsic cue underlying the binary choice between these two division modes remains elusive. Here we show evidence in Caenorhabditis elegans that the invariable lineage of the division modes is programmed by the balance between antagonizing complexes of partitioning-defective (PAR) proteins. By uncoupling unequal inheritance of PAR proteins from that of fate determinants during zygote division, we demonstrated that changes in the balance between PAR-2 and PAR-6 are sufficient to re-program the division modes from symmetric to asymmetric and vice versa in two-cell stage embryos. The division mode adopted occurs independently of asymmetry in cytoplasmic fate determinants, cell-size asymmetry, and cell-cycle asynchrony between the sister cells. We propose that the balance between antagonizing PAR proteins represents an intrinsic self-organizing cue for binary specification of the division modes during development.

scholarly journals The type II integral ER membrane protein VAP-B homolog in C. elegans is cleaved to release the N-terminal MSP domain to signal non-cell-autonomously

2021 ◽  
Vol 470 ◽  
pp. 10-20
Author(s):  
Hala Zein-Sabatto ◽  
Tim Cole ◽  
Hieu D. Hoang ◽  
Ekta Tiwary ◽  
Chenbei Chang ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Type Ii ◽  
C Elegans ◽  
Er Membrane

scholarly journals An endoplasmic reticulum (ER) ATPase safeguards ER identity by removing ectopically localized mitochondrial proteins

2020 ◽  
Author(s):  
Qing Qin ◽  
Ting Zhao ◽  
Wei Zou ◽  
Kang Shen ◽  
Xiangming Wang
Keyword(s):  
Mitochondrial Membrane ◽  
Mitochondrial Proteins ◽  
Dependent Manner ◽  
Related Protein ◽  
C Elegans ◽  
Dendrite Development ◽  
Dendritic Arbors ◽  
Dendrite Morphogenesis ◽  
Surveillance Mechanism ◽  
Er Membrane

SUMMARYStringent targeting of membrane proteins to corresponding organelles is essential for organelle identity and functions. In addition to molecular pathways that target proteins to appropriate organelles, surveillance mechanisms clear mistargeted proteins from undesired destinations. While Msp1 functions on mitochondrial membrane to remove mistargeted proteins, the surveillance mechanism for the ER is not well understood. Here, we show that mitochondrial tail-anchored (TA) and signal-anchored (SA) proteins mislocalize to ER membrane in neurons and muscles in C. elegans catp-8 mutants. catp-8 encodes a conserved P5A type ATPase, which localizes to ER and removes ectopic mitochondrial TA/SA proteins from ER. In catp-8 mutant, mitochondria fission protein FIS-1 mislocalizes to ER membrane. Together with another mitochondria fission protein MFF-2, FIS-1 causes ER fragmentation in a Dynamin related protein (DRP-1) dependent manner. Additionally, CATP-8 is essential for dendrite development. catp-8 mutant dramatically reduces the level of the dendrite guidance receptor DMA-1, leading to diminished dendritic arbors. Hence, P5A ATPase safeguards ER morphology and functions by preventing mitochondrial proteins mislocalization.HIGHLIGHTSCATP-8, a P5A type ATPase, localizes to ER and functions as a surveillance mechanism to remove mistargeted mitochondrial proteins.Multiple mitochondria proteins are mistargeted to ER in catp-8 mutants.Ectopic recruitment of mitochondria fission mechinary to ER causes ER fragmentation in catp-8 mutants.CATP-8 is essential for PVD dendrite morphogenesis through modulating the level of transmembrane receptor DMA-1.

scholarly journals ER stress sensor Ire1 deploys a divergent transcriptional program in response to lipid bilayer stress

2019 ◽  
Author(s):  
Nurulain Ho ◽  
Haoxi Wu ◽  
Jiaming Xu ◽  
Jhee Hong Koh ◽  
Wei Sheng Yap ◽  
...  
Keyword(s):  
Lipid Bilayer ◽  
Metabolic Diseases ◽  
Membrane Integrity ◽  
Membrane Lipid ◽  
C Elegans ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response ◽  
Yeast Mutants ◽  
Er Membrane

SUMMARYMembrane integrity at the endoplasmic reticulum (ER) is tightly regulated and is implicated in metabolic diseases when compromised. Using an engineered sensor that exclusively activates the unfolded protein response (UPR) during aberrant ER membrane lipid composition, we identified pathways beyond lipid metabolism that are necessary to maintain ER integrity in yeast and are conserved in C. elegans. To systematically validate yeast mutants disrupting ER membrane homeostasis, we identified a lipid bilayer stress (LBS) sensing switch in the UPR transducer protein Ire1, located at the interface of the amphipathic and transmembrane helices. Furthermore, transcriptome and chromatin immunoprecipitation (ChIP) analyses pinpoint the UPR as a broad-spectrum compensatory pathway in which LBS and proteotoxic stress-induced UPR deploy divergent transcriptional programs. Together, these findings reveal the UPR program as the sum of two independent stress events and could be exploited for future therapeutic intervention.

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