scholarly journals The inositol 5-phosphatase INPP5K participates in the fine control of ER organization

2018 ◽  
Vol 217 (10) ◽  
pp. 3577-3592 ◽  
Author(s):  
Rui Dong ◽  
Ting Zhu ◽  
Lorena Benedetti ◽  
Swetha Gowrishankar ◽  
Huichao Deng ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Caenorhabditis Elegans ◽  
Independent Study ◽  
Mutant Phenotype ◽  
Network Organization ◽  
Wild Type ◽  
Fine Control

INPP5K (SKIP) is an inositol 5-phosphatase that localizes in part to the endoplasmic reticulum (ER). We show that recruitment of INPP5K to the ER is mediated by ARL6IP1, which shares features of ER-shaping proteins. Like ARL6IP1, INPP5K is preferentially localized in ER tubules and enriched, relative to other ER resident proteins (Sec61β, VAPB, and Sac1), in newly formed tubules that grow along microtubule tracks. Depletion of either INPP5K or ARL6IP1 results in the increase of ER sheets. In a convergent but independent study, a screen for mutations affecting the distribution of the ER network in dendrites of the PVD neurons of Caenorhabditis elegans led to the isolation of mutants in CIL-1, which encodes the INPP5K worm orthologue. The mutant phenotype was rescued by expression of wild type, but not of catalytically inactive CIL-1. Our results reveal an unexpected role of an ER localized polyphosphoinositide phosphatase in the fine control of ER network organization.

Touch insensitive foraging of Caenorhabditis elegans in a constrained structure

Nematology ◽  
2009 ◽  
Vol 11 (4) ◽  
pp. 551-554
Author(s):  
Jinu Eo ◽  
Kazunori Otobe
Keyword(s):  
Caenorhabditis Elegans ◽  
Natural Habitat ◽  
The Body ◽  
Wild Type ◽  
Agar Gel ◽  
Touch Sensor ◽  
Foraging Pattern

Abstract The objective of this study was to clarify the role of touch sensors in the foraging of Caenorhabditis elegans in a constrained structure. The strains tested included an array of mechanosensory mutants insensitive to touch in the body, tail or nose. The mutants and wild type nematodes repeated forward and backward movement in a micro-moulded substrate as on the surface of agar gel. Differences in the foraging pattern were not obvious among mutant groups having different touch sensor deficit in the substrate, and all strains of nematode successfully moved out of the T-shaped structure after searching the configuration of their environment. The results suggest that the touch sensor is a weak contributor to the performance of the worms when foraging, and the behaviour is governed by intrinsic spontaneous patterns in the absence of any stimuli in natural habitat.

Role of O-GlcNAcylation and endoplasmic reticulum stress on obesity and insulin resistance

2019 ◽  
Vol 44 (5) ◽  
pp. 599-610 ◽  
Author(s):  
Benan Pelin Sermikli ◽  
Gulizar Aydogdu ◽  
Afsar Abbasi Taghidizaj ◽  
Erkan Yilmaz
Keyword(s):  
Insulin Resistance ◽  
Endoplasmic Reticulum ◽  
Western Blot ◽  
Er Stress ◽  
Insulin Receptor ◽  
Serine Phosphorylation ◽  
Wild Type ◽  
Adipose Tissues ◽  
Insulin Resistant

Abstract Background Obesity is a global public health problem. Obesity closely associated with various metabolic diseases such as; insulin resistance, hypertension, dyslipidemia and cardiovascular diseases. Endoplasmic reticulum (ER) stress is a critical factor for insulin resistance. O-linked N-acetyl-glucosamine (O-GlcNAc); is the post-translational modification which is has a vital role in biological processes; including cell signaling, in response to nutrients, stress and other extracellular stimuli. Materials and methods In this study, we aimed to investigate the role of O-GlcNAc modification in the context of obesity and obesity-associated insulin resistance in adipose tissue. For this purpose, first, the visceral and epididymal adipose tissues of obese and insulin resistant C57BL/6 Lepob/Lepob and wild-type mice were used to determine the O-GlcNAc modification pattern by western blot. Secondly, the external stimulation of O-GlcNAc modification in wild-type mice achieved by intraperitoneal 5 mg/kg/day glucosamine injection every 24 h for 5 days. The effect of increased O-GlcNAc modification on insulin resistance and ER stress investigated in adipose tissues of glucosamine challenged wild-type mice through regulation of the insulin signaling pathway and unfolded protein response (UPR) elements by western blot. In addition to that, the O-GlcNAc status of the insulin receptor substrate-1 (IRS1) investigated in epididymal and visceral adipose tissues of ob/ob, wild-type and glucosamine challenged mice by immunoprecipitation. Results We found that reduced O-GlcNAc levels in visceral and epididymal adipose tissues of obese and insulin-resistant ob/ob mice, although interestingly we observed that increased O-GlcNAc modification in glucosamine challenged wild-type mice resulted in insulin resistance and ER stress. Furthermore, we demonstrated that the IRS1 was modified with O-GlcNAc in visceral and epididymal adipose tissues in both ob/ob mice and glucosamine-injected mice, and was compatible with the serine phosphorylation of this modification. Conclusion Our results suggest that O-GlcNAcylation of proteins is a crucial factor for intracellular trafficking regulates insulin receptor signaling and UPR depending on the cellular state of insulin resistance.

scholarly journals Effects of ubiquitin C-terminal hydrolase L1 deficiency on mouse ova

Reproduction ◽  
2012 ◽  
Vol 143 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Sayaka Koyanagi ◽  
Hiroko Hamasaki ◽  
Satoshi Sekiguchi ◽  
Kenshiro Hara ◽  
Yoshiyuki Ishii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Proteomic Analysis ◽  
Ubiquitin Proteasome System ◽  
Underlying Mechanism ◽  
Wild Type ◽  
Transmission Electron ◽  
Ubiquitin Proteasome

Maternal proteins are rapidly degraded by the ubiquitin–proteasome system during oocyte maturation in mice. Ubiquitin C-terminal hydrolase L1 (UCHL1) is highly and specifically expressed in mouse ova and is involved in the polyspermy block. However, the role of UCHL1 in the underlying mechanism of polyspermy block is poorly understood. To address this issue, we performed a comprehensive proteomic analysis to identify maternal proteins that were relevant to the role of UCHL1 in mouse ova using UCHL1-deficientgad. Furthermore, we assessed morphological features ingadmouse ova using transmission electron microscopy. NACHT, LRR, and PYD domain-containing (NALP) family proteins and endoplasmic reticulum (ER) chaperones were identified by proteomic analysis. We also found that the ‘maternal antigen that embryos require’ (NLRP5 (MATER)) protein level increased significantly ingadmouse ova compared with that in wild-type mice. In an ultrastructural study,gadmouse ova contained less ER in the cortex than in wild-type mice. These results provide new insights into the role of UCHL1 in the mechanism of polyspermy block in mouse ova.

scholarly journals Aurora-A kinase is required for centrosome maturation in Caenorhabditis elegans

2001 ◽  
Vol 155 (7) ◽  
pp. 1109-1116 ◽  
Author(s):  
Eva Hannak ◽  
Matthew Kirkham ◽  
Anthony A. Hyman ◽  
Karen Oegema
Keyword(s):  
Caenorhabditis Elegans ◽  
Fluorescence Intensity ◽  
Maturation Process ◽  
Aurora A Kinase ◽  
Aurora A ◽  
Wild Type ◽  
C Elegans ◽  
Nuclear Envelope Breakdown ◽  
Pericentriolar Material

Centrosomes mature as cells enter mitosis, accumulating γ-tubulin and other pericentriolar material (PCM) components. This occurs concomitant with an increase in the number of centrosomally organized microtubules (MTs). Here, we use RNA-mediated interference (RNAi) to examine the role of the aurora-A kinase, AIR-1, during centrosome maturation in Caenorhabditis elegans. In air-1(RNAi) embryos, centrosomes separate normally, an event that occurs before maturation in C. elegans. After nuclear envelope breakdown, the separated centrosomes collapse together, and spindle assembly fails. In mitotic air-1(RNAi) embryos, centrosomal α-tubulin fluorescence intensity accumulates to only 40% of wild-type levels, suggesting a defect in the maturation process. Consistent with this hypothesis, we find that AIR-1 is required for the increase in centrosomal γ-tubulin and two other PCM components, ZYG-9 and CeGrip, as embryos enter mitosis. Furthermore, the AIR-1–dependent increase in centrosomal γ-tubulin does not require MTs. These results suggest that aurora-A kinases are required to execute a MT-independent pathway for the recruitment of PCM during centrosome maturation.

scholarly journals Dysfunctionality of a tobacco mosaic virus movement protein mutant mimicking threonine 104 phosphorylation

2003 ◽  
Vol 84 (3) ◽  
pp. 727-732 ◽  
Author(s):  
E. M. Karger ◽  
O. Yu. Frolova ◽  
N. V. Fedorova ◽  
L. A. Baratova ◽  
T. V. Ovchinnikova ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Movement ◽  
Specific Protein ◽  
Virus Movement ◽  
Wild Type ◽  
Molecular Masses

Replication of tobacco mosaic virus (TMV) is connected with endoplasmic reticulum (ER)-associated membranes at early stages of infection. This study reports that TMV movement protein (MP)-specific protein kinases (PKs) associated with the ER of tobacco were capable of phosphorylating Thr104 in TMV MP. The MP-specific PKs with apparent molecular masses of about 45–50 kDa and 38 kDa were revealed by gel PK assays. Two types of mutations were introduced in TMV MP gene of wild-type TMV U1 genome to substitute Thr104 by neutral Ala or by negatively charged Asp. Mutation of Thr104 to Ala did not affect the size of necrotic lesions induced by the mutant virus in Nicotiana tabacum Xanthi nc. plants. Conversely, mutation of Thr to Asp mimicking Thr104 phosphorylation strongly inhibited cell-to-cell movement. The possible role of Thr104 phosphorylation in TMV MP function is discussed.

scholarly journals A role for Rab5 in structuring the endoplasmic reticulum

2007 ◽  
Vol 178 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Anjon Audhya ◽  
Arshad Desai ◽  
Karen Oegema
Keyword(s):  
Endoplasmic Reticulum ◽  
Caenorhabditis Elegans ◽  
Nuclear Envelope ◽  
Rab Gtpases ◽  
C Elegans ◽  
Rab Family ◽  
Kinetics Of

The endoplasmic reticulum (ER) is a contiguous network of interconnected membrane sheets and tubules. The ER is differentiated into distinct domains, including the peripheral ER and nuclear envelope. Inhibition of two ER proteins, Rtn4a and DP1/NogoA, was previously shown to inhibit the formation of ER tubules in vitro. We show that the formation of ER tubules in vitro also requires a Rab family GTPase. Characterization of the 29 Caenorhabditis elegans Rab GTPases reveals that depletion of RAB-5 phenocopies the defects in peripheral ER structure that result from depletion of RET-1 and YOP-1, the C. elegans homologues of Rtn4a and DP1/NogoA. Perturbation of endocytosis by other means did not affect ER structure; the role of RAB-5 in ER morphology is thus independent of its well-studied requirement for endocytosis. RAB-5 and YOP-1/RET-1 also control the kinetics of nuclear envelope disassembly, which suggests an important role for the morphology of the peripheral ER in this process.

scholarly journals The PAF1 complex cell-autonomously promotes oogenesis in Caenorhabditis elegans

2021 ◽  
Author(s):  
Yukihiko Kubota ◽  
Natsumi Ota ◽  
Hisashi Takatsuka ◽  
Takuma Unno ◽  
Shuichi Onami ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Rna Polymerase Ii ◽  
Oocyte Maturation ◽  
Germ Line ◽  
Biological Processes ◽  
Wild Type ◽  
Expression Of Genes ◽  
A Cell ◽  
Precise Role

The RNA polymerase II-associated factor 1 complex (PAF1C) is a protein complex that consists of LEO1, RTF1, PAF1, CDC73, and CTR9, and has been shown to be involved in Pol II-mediated transcriptional and chromatin regulation. Although it has been shown to regulate a variety of biological processes, the precise role of the PAF1C during germ line development has not been clarified. In this study, we found that reduction in the function of the PAF1C components, LEO-1, RTFO-1, PAFO-1, CDC-73, and CTR-9, in Caenorhabditis elegans affects cell volume expansion of oocytes. Defects in oogenesis were also confirmed using an oocyte maturation marker, OMA-1::GFP. While four to five OMA-1::GFP-positive oocytes were observed in wild-type animals, their numbers were significantly decreased in pafo-1 mutantand leo-1(RNAi), cdc-73(RNAi), and pafo-1(RNAi) animals. Expression of a functional PAFO-1::mCherry transgene in the germline significantly rescued the oogenesis-defective phenotype of the pafo-1 mutants, suggesting that expression of the PAF1C in germ cells is required for oogenesis. Notably, overexpression of OMA-1::GFP partially rescued the oogenesis defect in the pafo-1 mutants. Based on our findings, we propose that the PAF1C promotes oogenesis in a cell-autonomous manner by positively regulating the expression of genes involved in oocyte maturation.

scholarly journals The Caenorhabditis elegans UNC-87 protein is essential for maintenance, but not assembly, of bodywall muscle.

1994 ◽  
Vol 127 (1) ◽  
pp. 71-78 ◽  
Author(s):  
S Goetinck ◽  
R H Waterston
Keyword(s):  
Monoclonal Antibodies ◽  
Caenorhabditis Elegans ◽  
Muscle Contraction ◽  
Gene Product ◽  
Heavy Chain ◽  
Structural Component ◽  
Muscle Proteins ◽  
Wild Type ◽  
Muscle Structure

Mutations in the unc-87 gene of Caenorhabditis elegans cause disorganization of the myofilament lattice in adult bodywall muscle. In order to assess the organization of specific bodywall muscle components in the absence of the unc-87 gene product, we examined the bodywall muscles of mutant animals using phalloidin and monoclonal antibodies to various muscle proteins. These studies indicated that the bodywall muscle of unc-87 embryos is initially almost wild type in its organization, but at later stages, the muscle becomes severely disorganized. To address the possibility that this disorganization is due to deterioration of the muscle as a result of contraction, we introduced into the unc-87 mutant background a mutation that decreases myosin heavy chain activity but does not substantially affect muscle structure. The improved muscle structure and motility of the double mutants are consistent with the hypothesis that at least part of the disorganization phenotype of unc-87 mutants is a consequence of the wild-type levels of force generated during muscle contraction. These results imply that the role of the unc-87 gene product is not in specifying organization but rather in serving as a structural component maintaining lattice integrity during and after contraction.

scholarly journals Analysis of the role of tra-1 in germline sex determination in the nematode Caenorhabditis elegans.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 755-769 ◽  
Author(s):  
T Schedl ◽  
P L Graham ◽  
M K Barton ◽  
J Kimble
Keyword(s):  
Caenorhabditis Elegans ◽  
Sex Determination ◽  
Germ Line ◽  
Temperature Sensitive ◽  
Loss Of Function ◽  
Wild Type ◽  
Allelic Series ◽  
Isolation And Characterization ◽  
Somatic Gonad

Abstract In wild-type Caenorhabditis elegans there are two sexes, self-fertilizing hermaphrodites (XX) and males (XO). To investigate the role of tra-1 in controlling sex determination in germline tissue, we have examined germline phenotypes of nine tra-1 loss-of-function (lf) mutations. Previous work has shown that tra-1 is needed for female somatic development as the nongonadal soma of tra-1(lf) XX mutants is masculinized. In contrast, the germline of tra-1(lf) XX and XO animals is often feminized; a brief period of spermatogenesis is followed by oogenesis, rather than the continuous spermatogenesis observed in wild-type males. In addition, abnormal gonadal (germ line and somatic gonad) phenotypes are observed which may reflect defects in development or function of somatic gonad regulatory cells. Analysis of germline feminization and abnormal gonadal phenotypes of the various mutations alone or in trans to a deficiency reveals that they cannot be ordered in an allelic series and they do not converge to a single phenotypic endpoint. These observations lead to the suggestion that tra-1 may produce multiple products and/or is autoregulated. One interpretation of the germline feminization is that tra-1(+) is necessary for continued specification of spermatogenesis in males. We also report the isolation and characterization of tra-1 gain-of-function (gf) mutations with novel phenotypes. These include temperature sensitive, recessive germline feminization, and partial somatic loss-of-function phenotypes.

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