scholarly journals Roles of the novel coiled-coil protein Rng10 in septum formation during fission yeast cytokinesis

2016 ◽  
Vol 27 (16) ◽  
pp. 2528-2541 ◽  
Author(s):  
Yajun Liu ◽  
I-Ju Lee ◽  
Mingzhai Sun ◽  
Casey A. Lower ◽  
Kurt W. Runge ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Rho Gtpases ◽  
Cellular Localization ◽  
Affinity Purification ◽  
Coiled Coil ◽  
The Novel ◽  
Septum Formation ◽  
Division Site ◽  
And Function

Rho GAPs are important regulators of Rho GTPases, which are involved in various steps of cytokinesis and other processes. However, regulation of Rho-GAP cellular localization and function is not fully understood. Here we report the characterization of a novel coiled-coil protein Rng10 and its relationship with the Rho-GAP Rga7 in fission yeast. Both rng10Δ and rga7Δ result in defective septum and cell lysis during cytokinesis. Rng10 and Rga7 colocalize on the plasma membrane at the cell tips during interphase and at the division site during cell division. Rng10 physically interacts with Rga7 in affinity purification and coimmunoprecipitation. Of interest, Rga7 localization is nearly abolished without Rng10. Moreover, Rng10 and Rga7 work together to regulate the accumulation and dynamics of glucan synthases for successful septum formation in cytokinesis. Our results show that cellular localization and function of the Rho-GAP Rga7 are regulated by a novel protein, Rng10, during cytokinesis in fission yeast.

scholarly journals Roles of putative Rho-GEF Gef2 in division-site positioning and contractile-ring function in fission yeast cytokinesis

2012 ◽  
Vol 23 (7) ◽  
pp. 1181-1195 ◽  
Author(s):  
Yanfang Ye ◽  
I-Ju Lee ◽  
Kurt W. Runge ◽  
Jian-Qiu Wu
Keyword(s):  
Fission Yeast ◽  
Rho Gtpases ◽  
Nucleotide Exchange ◽  
Contractile Ring ◽  
Division Plane ◽  
Cell Functions ◽  
Division Site ◽  
Ring Assembly ◽  
And Function ◽  
Rho Gef

Cytokinesis is crucial for integrating genome inheritance and cell functions. In multicellular organisms, Rho-guanine nucleotide exchange factors (GEFs) and Rho GTPases are key regulators of division-plane specification and contractile-ring formation during cytokinesis, but how they regulate early steps of cytokinesis in fission yeast remains largely unknown. Here we show that putative Rho-GEF Gef2 and Polo kinase Plo1 coordinate to control the medial cortical localization and function of anillin-related protein Mid1. The division-site positioning defects of gef2∆ plo1-ts18 double mutant can be partially rescued by increasing Mid1 levels. We find that Gef2 physically interacts with the Mid1 N-terminus and modulates Mid1 cortical binding. Gef2 localization to cortical nodes and the contractile ring depends on its last 145 residues, and the DBL-homology domain is important for its function in cytokinesis. Our data suggest the interaction between Rho-GEFs and anillins is an important step in the signaling pathways during cytokinesis. In addition, Gef2 also regulates contractile-ring function late in cytokinesis and may negatively regulate the septation initiation network. Collectively, we propose that Gef2 facilitates and stabilizes Mid1 binding to the medial cortex, where the localized Mid1 specifies the division site and induces contractile-ring assembly.

scholarly journals The novel RacE-binding protein GflB sharpens Ras activity at the leading edge of migrating cells

2016 ◽  
Vol 27 (10) ◽  
pp. 1596-1605 ◽  
Author(s):  
Hiroshi Senoo ◽  
Huaqing Cai ◽  
Yu Wang ◽  
Hiromi Sesaki ◽  
Miho Iijima
Keyword(s):  
Rho Gtpases ◽  
Rho Gtpase ◽  
Gene Knockout ◽  
Binding Protein ◽  
Affinity Purification ◽  
Leading Edge ◽  
The Novel ◽  
Gradient Sensing ◽  
Signaling Events ◽  
Migrating Cells

Directional sensing, a process in which cells convert an external chemical gradient into internal signaling events, is essential in chemotaxis. We previously showed that a Rho GTPase, RacE, regulates gradient sensing in Dictyostelium cells. Here, using affinity purification and mass spectrometry, we identify a novel RacE-binding protein, GflB, which contains a Ras GEF domain and a Rho GAP domain. Using biochemical and gene knockout approaches, we show that GflB balances the activation of Ras and Rho GTPases, which enables cells to precisely orient signaling events toward higher concentrations of chemoattractants. Furthermore, we find that GflB is located at the leading edge of migrating cells, and this localization is regulated by the actin cytoskeleton and phosphatidylserine. Our findings provide a new molecular mechanism that connects directional sensing and morphological polarization.

scholarly journals Structural biology of laminins

2019 ◽  
Vol 63 (3) ◽  
pp. 285-295 ◽  
Author(s):  
Erhard Hohenester
Keyword(s):  
Structural Biology ◽  
Coiled Coil ◽  
Large Cell ◽  
Basement Membranes ◽  
Cell Adhesive ◽  
A Cell ◽  
The Cross ◽  
And Function ◽  
Polypeptide Chains

Abstract Laminins are large cell-adhesive glycoproteins that are required for the formation and function of basement membranes in all animals. Structural studies by electron microscopy in the early 1980s revealed a cross-shaped molecule, which subsequently was shown to consist of three distinct polypeptide chains. Crystallographic studies since the mid-1990s have added atomic detail to all parts of the laminin heterotrimer. The three short arms of the cross are made up of continuous arrays of disulphide-rich domains. The globular domains at the tips of the short arms mediate laminin polymerization; the surface regions involved in this process have been identified by structure-based mutagenesis. The long arm of the cross is an α-helical coiled coil of all three chains, terminating in a cell-adhesive globular region. The molecular basis of cell adhesion to laminins has been revealed by recent structures of heterotrimeric integrin-binding fragments and of a laminin fragment bound to the carbohydrate modification of dystroglycan. The structural characterization of the laminin molecule is essentially complete, but we still have to find ways of imaging native laminin polymers at molecular resolution.

scholarly journals Phosphoregulation of tropomyosin is crucial for actin cable turnover and division site placement

2019 ◽  
Vol 218 (11) ◽  
pp. 3548-3559 ◽  
Author(s):  
Saravanan Palani ◽  
Darius V. Köster ◽  
Tomoyuki Hatano ◽  
Anton Kamnev ◽  
Taishi Kanamaru ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Actin Filaments ◽  
Coiled Coil ◽  
Actin Binding ◽  
Division Site ◽  
Actin Cable ◽  
Nonmuscle Cells ◽  
The Stability ◽  
Actin Cables

Tropomyosin is a coiled-coil actin binding protein key to the stability of actin filaments. In muscle cells, tropomyosin is subject to calcium regulation, but its regulation in nonmuscle cells is not understood. Here, we provide evidence that the fission yeast tropomyosin, Cdc8, is regulated by phosphorylation of a serine residue. Failure of phosphorylation leads to an increased number and stability of actin cables and causes misplacement of the division site in certain genetic backgrounds. Phosphorylation of Cdc8 weakens its interaction with actin filaments. Furthermore, we show through in vitro reconstitution that phosphorylation-mediated release of Cdc8 from actin filaments facilitates access of the actin-severing protein Adf1 and subsequent filament disassembly. These studies establish that phosphorylation may be a key mode of regulation of nonmuscle tropomyosins, which in fission yeast controls actin filament stability and division site placement.

scholarly journals The Golgin Protein RUD3 Regulates Fusarium graminearum Growth and Virulence

2021 ◽  
Vol 87 (6) ◽  
Author(s):  
Chenyu Wang ◽  
Yao Wang ◽  
Liyuan Zhang ◽  
Ziyi Yin ◽  
Yuancun Liang ◽  
...  
Keyword(s):  
Fusarium Graminearum ◽  
Vegetative Growth ◽  
Mammalian Cells ◽  
Cellular Localization ◽  
Pathogenic Fungus ◽  
Coiled Coil ◽  
Effective Control ◽  
Content Type ◽  
Ascospore Discharge ◽  
And Function

ABSTRACT Golgins are coiled-coil proteins that play prominent roles in maintaining the structure and function of the Golgi complex. However, the role of golgin proteins in phytopathogenic fungi remains poorly understood. In this study, we functionally characterized the Fusarium graminearum golgin protein RUD3, a homolog of ScRUD3/GMAP-210 in Saccharomyces cerevisiae and mammalian cells. Cellular localization observation revealed that RUD3 is located in the cis-Golgi. Deletion of RUD3 caused defects in vegetative growth, ascospore discharge, deoxynivalenol (DON) production, and virulence. Moreover, the Δrud3 mutant showed reduced expression of tri genes and impairment of the formation of toxisomes, both of which play essential roles in DON biosynthesis. We further used green fluorescent protein (GFP)-tagged SNARE protein SEC22 (SEC22-GFP) as a tool to study the transport between the endoplasmic reticulum (ER) and Golgi and observed that SEC22-GFP was retained in the cis-Golgi in the Δrud3 mutant. RUD3 contains the coiled coil (CC), GRAB-associated 2 (GA2), GRIP-related Arf binding (GRAB), and GRAB-associated 1 (GA1) domains, which except for GA1, are indispensable for normal localization and function of RUD3, whereas only CC is essential for normal RUD3-RUD3 interaction. Together, these results demonstrate how the golgin protein RUD3 mediates retrograde trafficking in the ER-to-Golgi pathway and is necessary for growth, ascospore discharge, DON biosynthesis, and pathogenicity in F. graminearum. IMPORTANCE Fusarium head blight (FHB) caused by the fungal pathogen Fusarium graminearum is an economically important disease of wheat and other small grain cereal crops worldwide, and limited effective control strategies are available. A better understanding of the regulation mechanisms of F. graminearum development, deoxynivalenol (DON) biosynthesis, and pathogenicity is therefore important for the development of effective control management of this disease. Golgins are attached via their extreme carboxy terminus to the Golgi membrane and are involved in vesicle trafficking and organelle maintenance in eukaryotic cells. In this study, we systematically characterized a highly conserved Golgin protein, RUD3, and found that it is required for vegetative growth, ascospore discharge, DON production, and pathogenicity in F. graminearum. Our findings provide a comprehensive characterization of the golgin family protein RUD3 in plant-pathogenic fungus, which could help to identify a new potential target for effective control of this devastating disease.

scholarly journals Multimodality diagnosis of cardiac involvement in COVID-19 patients

2021 ◽  
Vol 31 (1) ◽  
pp. 17-26
Author(s):  
Anca Balinisteanu ◽  
Hayat Memis ◽  
Gratiela Postulache-Cosmulescu ◽  
Diana Mihalcea ◽  
Sorina Mihaila ◽  
...  
Keyword(s):  
Myocardial Injury ◽  
Wide Spectrum ◽  
Multiorgan Failure ◽  
Cardiovascular Complications ◽  
Cardiac Biomarkers ◽  
The Novel ◽  
Correct Treatment ◽  
And Function

The Coronavirus disease 2019 (COVID-19) pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), exhibits a wide spectrum of manifestations, from asymptomatic presentations to acute respiratory failure, myocardial injury, arterial or venous thrombosis, multiorgan failure, and death. Although COVID-19 mainly disrupts the respiratory syndrome, it has been shown to have detrimental impact on cardiac morphology and function, resulting in a broad range of cardiovascular complications and poor outcome, increasing morbidity and mortality of these patients. This review will summarize the knowledge on characterization of myocardial injury in COVID 19, by using cardiac biomarkers, electrocardiographic, and cardiac multi-modality imaging findings for an early and accurate diagnosis, proper management, correct treatment, and follow-up of COVID-19 patients.

scholarly journals Affinity purification of the novel cysteine proteinase papaya proteinase IV, and papain from papaya latex

1989 ◽  
Vol 261 (2) ◽  
pp. 469-476 ◽  
Author(s):  
D J Buttle ◽  
A A Kembhavi ◽  
S L Sharp ◽  
R E Shute ◽  
D H Rich ◽  
...  
Keyword(s):  
Cysteine Proteinase ◽  
Affinity Purification ◽  
Molecular Size ◽  
Exchange Chromatography ◽  
The Novel ◽  
Protein Substrates ◽  
Papaya Latex ◽  
Sepharose 4B ◽  
Spray Dried

A procedure is described for the purification of a previously undetected cysteine proteinase, which we have called papaya proteinase IV, from spray-dried latex of the papaya (Carica papaya) plant. The purification involves affinity chromatography on Gly-Phe-aminoacetonitrile linked to CH-Sepharose 4B, with elution by 2-hydroxyethyl disulphide at pH 4.5. The product thus obtained is a mixture of almost fully active papain and papay proteinase IV, which are then separated by cation-exchange chromatography. A preliminary characterization of papaya proteinase IV showed it to be very similar to chymopapain in both molecular size and charge. However, the new enzyme is immunologically distinct from the previously characterized cysteine proteinases of papaya latex. It also differs in its lack of activity against the synthetic substrates of the other papaya proteinases, in its narrow specificity against protein substrates and its lack of inhibition by chicken cystatin. Papaya proteinase IV is abundant, contributing almost 30% of the protein in spray-dried papaya latex, and contamination of chymopapain preparations with this enzyme may account for some of the previously reported heterogeneity of chymopapain.

scholarly journals Beyond classic editing: innovative CRISPR approaches for functional studies of long non-coding RNA

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Dahlia A Awwad
Keyword(s):  
Genetic Manipulation ◽  
Functional Characterization ◽  
The Novel ◽  
Functional Studies ◽  
Non Coding Rna ◽  
Rna Targeting ◽  
Potential Applications ◽  
And Function ◽  
Long Non Coding Rna

Abstract Long non-coding RNAs (lncRNAs) makeup a considerable part of the non-coding human genome and had been well-established as crucial players in an array of biological processes. In spite of their abundance and versatile roles, their functional characteristics remain largely undiscovered mainly due to the lack of suitable genetic manipulation tools. The emerging CRISPR/Cas9 technology has been widely adapted in several studies that aim to screen and identify novel lncRNAs as well as interrogate the functional properties of specific lncRNAs. However, the complexity of lncRNAs genes and the regulatory mechanisms that govern their transcription, as well as their unique functionality pose several limitations the utilization of classic CRISPR methods in lncRNAs functional studies. Here, we overview the unique characteristics of lncRNAs transcription and function and the suitability of the CRISPR toolbox for applications in functional characterization of lncRNAs. We discuss some of the novel variations to the classic CRISPR/Cas9 system that have been tailored and applied previously to study several aspects of lncRNAs functionality. Finally, we share perspectives on the potential applications of various CRISPR systems, including RNA-targeting, in the direct editing and manipulation of lncRNAs.

scholarly journals Micro/Nanoscale Tribological and Mechanical Investigation of the Articular Surfaces of Katydid Leg Joints: Potential for the Novel Bioinspired Lubrication Systems

MRS Advances ◽  
2017 ◽  
Vol 2 (19-20) ◽  
pp. 1117-1123 ◽  
Author(s):  
Jun Kyun Oh ◽  
Cengiz Yegin ◽  
Mustafa Akbulut
Keyword(s):  
Hierarchical Structures ◽  
Surface Characteristics ◽  
The Novel ◽  
Periodic Patterns ◽  
Real Area Of Contact ◽  
Dry Conditions ◽  
Mechanical Investigation ◽  
Micromechanical Systems ◽  
And Function

ABSTRACTInsects are recognized with their ability to efficiently move, operate, and function, and hence are inspiration for the design of micromechanical systems. This work deals with the structural, mechanical, and frictional characterization of the leg joint articulations of the katydid (Orthoptera: Tettigoniidae). For the katydids, the tibia joints were found to show a nanosmooth texture while the femur joint had a micro/nanotextured surface characteristics. The nanotexture was a two-tone periodic patterns with the hierarchical structures involving cylindrical ridges that are covered with nanoscale lamellar patterns perpendicular to the long axis and valleys between ridges that are decorated with the hillock patterns. The tibia and femur contact regions showed the reduced elastic modulus (Er) values ranging from 0.88 ± 0.01 GPa to 3.90 ± 0.11 GPa. The friction coefficient (μ) value of 0.053 ± 0.001 was recorded for the sliding contact of the tibia joint against the femur joint in air under dry conditions. The low friction values are attributed to the reduced real area of contact between the joint pair due to the coupling of the nanosmooth surfaces against the hierarchically nanotextured surfaces.

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