Read by QxMD icon Read

Journal of Cell Science

Francesco Consolato, Francesca Maltecca, Susanna Tulli, Irene Sambri, Giorgio Casari
The proteolytic processing of dynamin like GTPase OPA1, mediated by the activity of both YME1L1 ( i- AAA protease complex) and OMA1, is a crucial step in the regulation of mitochondrial dynamics. OMA1 is a zinc metallopeptidase of the inner mitochondrial membrane that undergoes pre-activating proteolytic and auto-proteolytic cleavage after mitochondrial import. Here, we identify AFG3L2 ( m- AAA complex) as the major protease mediating this event by maturing the pre-pro-OMA1 of 60 kDa to the pro-OMA1 form of 40 kDa by severing the amino-terminal part without recognizing specific consensus sequence...
March 15, 2018: Journal of Cell Science
Tomoyuki Hatano, Salvatore Alioto, Emanuele Roscioli, Saravanan Palani, Scott T Clarke, Anton Kamnev, Juan Ramon Hernandez-Fernaud, Lavanya Sivashanmugam, Bernardo Chapa-Y-Lazo, Alexandra M E Jones, Robert C Robinson, Karuna Sampath, Masanori Mishima, Andrew D McAinsh, Bruce L Goode, Mohan K Balasubramanian
Actins are major eukaryotic cytoskeletal proteins, which perform many important cell functions, including cell division, cell polarity, wound healing, and muscle contraction. Despite obvious drawbacks, muscle actin, which is easily purified, is used extensively presently for biochemical studies of actin cytoskeleton from other organisms / cell types. Here we report a rapid and cost-effective method to purify heterologous actins expressed in the yeast Pichia pastoris Actin is expressed as a fusion with the actin-binding protein thymosin β4 and purified using an affinity tag introduced in the fusion...
March 13, 2018: Journal of Cell Science
Emily K Herman, Lyto Yiangou, Diego M Cantoni, Christopher N Miller, Francine Marciano-Cabral, Erin Anthonyrajah, Joel B Dacks, Anastasios D Tsaousis
Although the Golgi apparatus has a conserved morphology of flattened stacked cisternae in most eukaryotes, it has lost the stacked organization in several lineages, raising the question of what range of morphologies is possible for the Golgi. In order to understand this diversity, it is necessary to characterise the Golgi in many different lineages. Here we identify the Golgi apparatus in Naegleria , the first description of an unstacked Golgi organelle in a non-parasitic eukaryote, other than fungi. We provide a comprehensive list of Golgi-associated membrane trafficking genes encoded in two species of Naegleria and show that nearly all are expressed in mouse-passaged N...
March 13, 2018: Journal of Cell Science
Neha Saxena, Pankaj Mogha, Silalipi Dash, Abhijit Majumder, Sameer Jadhav, Shamik Sen
Efficient homing of human mesenchymal stem cells (hMSCs) is likely to be dictated by the combination of physical and chemical factors present in the microenvironment. However, the crosstalk between the physical and chemical cues remains incompletely understood. Here, we address this question by probing the efficiency of epidermal growth factor (EGF)-induced hMSC chemotaxis on substrates of varying stiffness (3, 30 and 600 kPa, respectively) inside a PDMS microfluidic device. Chemotactic speed was found to be the sum of a stiffness-dependent component and a chemotactic component...
March 13, 2018: Journal of Cell Science
Yoshihiko Kuchitsu, Yuta Homma, Naonobu Fujita, Mitsunori Fukuda
Macroautophagy (simply called autophagy hereafter) is an intracellular degradation mechanism that is activated by nutrient starvation. Although it is well-known that starvation induces autophagosome formation in an mTORC1-dependent manner, whether starvation also regulates autophagosome/autolysosome maturation was unclear. In the present study we succeeded in demonstrating that starvation activates autolysosome maturation in mammalian cells. We found that knockout (KO) of Rab7 caused accumulation of a massive number of LC3-positive autolysosomes under nutrient-rich conditions, indicating that Rab7 is dispensable for autophagosome-lysosome fusion...
March 7, 2018: Journal of Cell Science
Veronica J Larsson, Mohammed Hakim Jafferali, Balaje Vijayaraghavan, Ricardo A Figueroa, Einar Hallberg
We have investigated a possible role of the inner nuclear membrane protein, Samp1, in the mitotic machinery. Live cell imaging showed that Samp1aYFP distributed as filamentous structures in the mitotic spindle, partially co-localising with ß-tubulin. Samp1 depletion resulted in an increased frequency of cells with signs of chromosomal mis-segregation and prolonged metaphase, indicating problems with spindle assembly and/or chromosomal alignment. Consistently, mitotic spindles in Samp1 depleted cells contained significantly lower levels of ß-tubulin and γ-tubulin, phenotypes which were rescued by overexpression of Samp1aYFP...
March 7, 2018: Journal of Cell Science
Bhargavi Manda, Hina Mir, Ruchika Gangwar, Avtar S Meena, Shrunali Amin, Pradeep K Shukla, Kesha Dalal, Takuya Suzuki, Radha Krishna Rao
The apical junctional complex (AJC), which includes tight junction (TJ) and adherens junction (AJ) determine the epithelial polarity, cell-cell adhesion and permeability barrier. An intriguing characteristic of TJ is the dynamic nature of its multiprotein complex. Occludin is the most mobile TJ protein, but its significance in TJ dynamics is poorly understood. On the basis of phosphorylation sites we distinguished a sequence in the C-terminal domain of occludin as a regulatory motif (ORM). Deletion of ORM and expression of deletion mutant occludin in renal and intestinal epithelia reduced the mobility of occludin at the TJ...
March 5, 2018: Journal of Cell Science
Varun Jayeshkumar Shah, Subbareddy Maddika
Cullin-RING E3 ligases (CRLs) control broad range of biological processes by ubiquitinating numerous cellular substrates. However, role of CRL E3 ligases in chromatid cohesion is unknown. In this study, we identified a new CRL type E3 ligase (designated as CRL7SMU1 complex) that has an essential role in maintenance of chromatid cohesion. We demonstrate that SMU1, DDB1, CUL7 and RNF40 as integral components of this complex. SMU1 by acting as a substrate recognition module, binds to H2B and mediates monoubiquitination at K120 site through CRL7SMU1 E3 ligase complex...
March 5, 2018: Journal of Cell Science
Margarita Sobol, Alžběta Krausová, Sukriye Yildirim, Ilona Kalasová, Veronika Fáberová, Vladimír Vrkoslav, Vlada Philimonenko, Pavel Marášek, Lukáš Pastorek, Martin Čapek, Zuzana Lubovská, Lívia Uličná, Takuma Tsuji, Miroslav Lísa, Josef Cvačka, Toyoshi Fujimoto, Pavel Hozak
This paper describes a novel type of nuclear structures - nuclear lipid islets (NLIs). They are of 40-100 nm with a lipidic interior, and PtdIns(4,5)P2 molecules comprise a significant part of their surface. Most of NLIs have RNA at the periphery. Consistently with that, RNA is required for their integrity. NLI periphery is associated with Pol II transcription machinery, including the Pol II largest subunit, transcription factors, and NM1. The PtdIns(4,5)P2 -NM1 interaction is significant for Pol II transcription, since NM1 knock-down reduces the Pol II transcription level, and the overexpression of wild-type NM1 (but not NM1 mutated in the PtdIns(4,5)P2 -binding site) rescues the transcription...
March 5, 2018: Journal of Cell Science
Luke W Thompson, Kim D Morrison, Sally L Shirran, Ewout J N Groen, Tom H Gillingwater, Catherine H Botting, Judith E Sleeman
Spinal Muscular Atrophy (SMA) is an inherited neurodegenerative condition caused by reduction in functional Survival Motor Neurones Protein (SMN). SMN has been implicated in transport of mRNA in neural cells for local translation. We previously identified microtubule-dependant mobile vesicles rich in SMN and SmB, a member of the Sm family of snRNP-associated proteins, in neural cells. By comparing the interactomes of SmB and SmN, a neural-specific Sm protein, we now show that the essential neural protein neurochondrin (NCDN) interacts with Sm proteins and SMN in the context of mobile vesicles in neurites...
March 5, 2018: Journal of Cell Science
Ganapathi Kandasamy, Claes Andréasson
In protein quality control, proteotoxic misfolded proteins are recognized by molecular chaperones, ubiquitylated by dedicated quality-control ligases and delivered to 26S proteasome for degradation. The chaperone Hsp70 and its nucleotide exchange factor Hsp110 functions in the degradation of misfolded proteins by the ubiquitin-proteasome system via poorly understood mechanisms. Here we report that yeast Hsp110 (Sse1 and Sse2) functions in the degradation of Hsp70-associated ubiquitin conjugates at the post-ubiquitylation step and is required for the proteasomal degradation of ubiquitin-independent substrates...
March 5, 2018: Journal of Cell Science
Douglas Quilty, Calvin J Chan, Katherine Yurkiw, Alexandra Bain, Ghazal Babolmorad, Paul Melançon
We previously proposed a novel mechanism by which the enzyme Golgi-specific BFA resistance factor 1, or GBF1, is recruited to the membranes of the cis -Golgi based on in vivo experiments. Here, we extend the in vivo analysis on production of regulatory Arf•GDP and observe that ArfGAP2/3 do not play such a role. We confirm that Arf•GDP localization is critical as a TGN-localized Arf•GDP mutant protein fails to promote GBF1 recruitment. We also report the establishment of an in vitro GBF1 recruitment assay that supports regulation of GBF1 recruitment by Arf•GDP...
March 5, 2018: Journal of Cell Science
Rhian F Walther, Mubarik Burki, Noelia Pinal, Clare Rogerson, Franck Pichaud
In Drosophila epithelial cells, apical exclusion of Bazooka/Par3 defines the position of the Zonula Adherens (ZA), which demarcates the apical and lateral membrane and allows cells to assemble into sheets. Here, we show that the small GTPase Rap1, its effector AF6/Canoe (Cno) and the Cdc42-effector Pak4/Mushroom bodies tiny (Mbt), converge in regulating epithelial morphogenesis by coupling stabilization of the Adherens Junction (AJ) protein E-Cadherin, and Bazooka retention at the ZA Furthermore, our results show that the localization of Rap1, Cno and Mbt at the ZA is interdependent, indicating their functions during ZA morphogenesis are interlinked...
March 5, 2018: Journal of Cell Science
D K Jones, A Johnson, E C Roti Roti, F Liu, R Uelmen, R A Ayers, I Baczko, D J Tester, M J Ackerman, M C Trudeau, G A Robertson
Reduced levels of hERG protein and the corresponding repolarizing current IKr can cause arrhythmia and sudden cardiac death, but the underlying cellular mechanisms controlling hERG surface expression are not well understood. We identified TRIOBP-1, an F-actin binding protein previously associated with actin polymerization, as a putative hERG-interacting protein in a yeast-two hybrid screen of a cardiac library. We corroborated this interaction using Förster resonance energy transfer (FRET) in HEK293 cells and co-immunoprecipitation in HEK293 cells and native cardiac tissue...
March 5, 2018: Journal of Cell Science
Peter J M van Haastert, Ineke Keizer-Gunnink, Arjan Kortholt
Symmetry and symmetry breaking are essential in biology. Symmetry comes in different forms: rotational symmetry, mirror symmetry and alternating right/left symmetry. Especially the transitions between the different symmetry forms specify crucial points in cell biology, including gastrulation in development, formation of the cleavage furrow in cell division, or the front in cell polarity. However, the mechanisms of these symmetry transitions are not well understood. Here we have investigated the fundaments of symmetry and symmetry transitions of the cytoskeleton during cell movement...
February 27, 2018: Journal of Cell Science
Xiaoying Liang, Kevin J Hart, Gang Dong, Faiza A Siddiqui, Aswathy Sebastian, Xiaolian Li, Istvan Albert, Jun Miao, Scott E Lindner, Liwang Cui
In this study, we characterized a Puf family gene member, Puf3, in the malaria parasites Plasmodium falciparum and Plasmodium yoelii Secondary structure prediction suggested that the RNA-binding domains of Puf3s consisted of 11 pumilio repeats, similar to those in human Puf-A and yeast Puf6, which are involved in ribosome biogenesis. Neither pfpuf3 nor pypuf3 could be genetically disrupted, suggesting they may be essential for the intraerythrocytic developmental cycle. Cellular fractionation of PfPuf3 revealed preferential partitioning to the nuclear fraction, consistent with nuclear localization of PfPuf3::GFP and PyPuf3::GFP detected by immunofluorescence...
February 27, 2018: Journal of Cell Science
Zoe G Cardon, Elena L Peredo, Alice C Dohnalkova, Hannah L Gershone, Magdalena Bezanilla
Microscopic green algae inhabiting desert microbiotic crusts are remarkably diverse phylogenetically, and many desert lineages have independently evolved from aquatic ancestors. Here we worked with five desert and aquatic species within the family Scenedesmaceae to begin examining mechanisms underlying desiccation tolerance and release of unicellular vs. multicellular progeny. Live cell staining and time-lapse confocal imaging, coupled with transmission electron microscopy, established that the desert and aquatic species all divide by multiple (rather than binary) fission, though progeny were unicellular in three species, and multicellular (joined in a sheet-like coenobium) in two...
February 27, 2018: Journal of Cell Science
Poonam Sehgal, Xinyu Kong, Jun Wu, Raimon Sunyer, Xavier Trepat, Deborah Leckband
This study reports novel findings that link E-Cadherin-mediated force-transduction signaling to vinculin targeting to intercellular junctions via epidermal growth factor receptor (EGFR) and integrins. These results build on previous findings, which demonstrated that mechanically perturbed E-Cadherin receptors activate phosphoinositide-3-kinase and downstream integrins, in an EGFR-dependent manner. Results of this study show that this EGFR-mediated kinase cascade controls the force-dependent recruitment of vinculin to stressed E-Cadherin complexes--a key early signature of cadherin-based mechanotransduction...
February 27, 2018: Journal of Cell Science
Masatoshi Takagi, Takao Ono, Toyoaki Natsume, Chiyomi Sakamoto, Mitsuyoshi Nakao, Noriko Saitoh, Masato T Kanemaki, Tatsuya Hirano, Naoko Imamoto
Although condensins play essential roles in mitotic chromosome assembly, Ki-67, a protein localizing to the periphery of mitotic chromosomes, had also been shown to make a contribution to the process. To examine their respective roles, we generated a set of HCT116-based cell lines expressing Ki-67 and/or condensin subunits that were fused with an auxin-inducible degron for their conditional degradation. Both the localization and the dynamic behavior of Ki-67 on mitotic chromosomes were not largely affected upon depletion of condensin subunits, and vice versa...
February 27, 2018: Journal of Cell Science
Andrius Masedunskas, Mark A Appaduray, Christine A Lucas, María Lastra Cagigas, Marco Heydecker, Mira Holliday, Joyce Meiring, Jeff Hook, Anthony Kee, Melissa White, Paul Thomas, Yingfan Zhang, Robert S Adelstein, Tobias Meckel, Till Böcking, Roberto Weigert, Nicole S Bryce, Peter W Gunning, Edna C Hardeman
Many actin filaments in animal cells are co-polymers of actin and tropomyosin. For many of these co-polymers, non-muscle myosin II associates to establish a contractile network. However, the temporal relationship of these 3 proteins in the de novo assembly of actin filaments is not known. Intravital subcellular microscopy of secretory granule exocytosis allows the visualisation and quantitation of the formation of an actin scaffold in real time with the added advantage that it occurs in a living mammal, under physiological conditions...
February 27, 2018: Journal of Cell Science
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"