scholarly journals CsmA, a Class V Chitin Synthase with a Myosin Motor-like Domain, Is Localized through Direct Interaction with the Actin Cytoskeleton inAspergillus nidulans

2005 ◽  
Vol 16 (4) ◽  
pp. 1961-1970 ◽  
Author(s):  
Norio Takeshita ◽  
Akinori Ohta ◽  
Hiroyuki Horiuchi
Keyword(s):  
Cell Wall ◽  
Actin Cytoskeleton ◽  
Direct Interaction ◽  
Chitin Synthase ◽  
Structural Basis ◽  
Class V ◽  
Myosin Motor ◽  
Fungal Morphogenesis ◽  
Insight Into

One of the essential features of fungal morphogenesis is the polarized synthesis of cell wall components such as chitin. The actin cytoskeleton provides the structural basis for cell polarity in Aspergillus nidulans, as well as in most other eukaryotes. A class V chitin synthase, CsmA, which contains a myosin motor-like domain (MMD), is conserved among most filamentous fungi. The ΔcsmA null mutant showed remarkable abnormalities with respect to cell wall integrity and the establishment of polarity. In this study, we demonstrated that CsmA tagged with 9× HA epitopes localized near actin structures at the hyphal tips and septation sites and that its MMD was able to bind to actin. Characterization of mutants bearing a point mutation or deletion in the MMD suggests that the interaction between the MMD and actin is not only necessary for the proper localization of CsmA, but also for CsmA function. Thus, the finding of a direct interaction between the chitin synthase and the actin cytoskeleton provides new insight into the mechanisms of polarized cell wall synthesis and fungal morphogenesis.

scholarly journals Proliferation of Intrahyphal Hyphae Caused by Disruption ofcsmA, Which Encodes a Class V Chitin Synthase with a Myosin Motor-Like Domain in Aspergillus nidulans

1999 ◽  
Vol 181 (12) ◽  
pp. 3721-3729 ◽  
Author(s):  
Hiroyuki Horiuchi ◽  
Makoto Fujiwara ◽  
Shuichi Yamashita ◽  
Akinori Ohta ◽  
Masamichi Takagi
Keyword(s):  
Cell Wall ◽  
Aspergillus Nidulans ◽  
Wild Type Strain ◽  
Hyphal Growth ◽  
Chitin Synthase ◽  
Calcofluor White ◽  
Class V ◽  
Myosin Motor ◽  
Fungal Morphogenesis ◽  
Novel Protein

ABSTRACT We have found that the Aspergillus nidulans csmA gene encodes a novel protein which consists of an N-terminal myosin motor-like domain and a C-terminal chitin synthase domain (M. Fujiwara, H. Horiuchi, A. Ohta, and M. Takagi, Biochem. Biophys. Res. Commun. 236:75–78, 1997). To clarify the roles of csmA in fungal morphogenesis, we constructed csmA null mutants. The growth rate of the mutant colonies was almost the same as that of the wild-type strain, but hyphal growth was severely inhibited when a chitin-binding reagent, Calcofluor white or Congo red, was added to the medium. Moreover, morphological abnormalities in tip growth and septum formation were identified microscopically. Proliferation of intracellular new hyphae, called intrahyphal hyphae, which behaved as intrinsic hyphae, was the most striking phenotypic feature among them. These phenotypes were not suppressed when the only chitin synthase domain of csmA was expressed under the control of thealcA promoter, whereas they were suppressed when the intact form of csmA was expressed. Therefore, it was concluded that the product of csmA (CsmA) has important roles in polarized cell wall synthesis and maintenance of cell wall integrity and that the myosin motor-like domain is indispensable for these functions.

Identification of features associated with plant cell wall recalcitrance to pretreatment by alkaline hydrogen peroxide in diverse bioenergy feedstocks using glycome profiling

RSC Advances ◽  
2014 ◽  
Vol 4 (33) ◽  
pp. 17282-17292 ◽  
Author(s):  
Muyang Li ◽  
Sivakumar Pattathil ◽  
Michael G. Hahn ◽  
David B. Hodge
Keyword(s):  
Hydrogen Peroxide ◽  
Cell Wall ◽  
Cell Walls ◽  
Structural Organization ◽  
Plant Cell Wall ◽  
Structural Basis ◽  
Alkaline Hydrogen Peroxide ◽  
Glycome Profiling ◽  
Bioenergy Feedstocks ◽  
Insight Into

Glycome profiling was used to provide insight into the structural basis for how a mild alkaline-oxidative pretreatment may impact the composition and structural organization of the cell walls taxonomically diverse plants.

scholarly journals Isolation ofcsm1encoding a class V chitin synthase with a myosin motor-like domain from the rice blast fungus,Pyricularia oryzae

1999 ◽  
Vol 170 (1) ◽  
pp. 131-139 ◽  
Author(s):  
In Cheol Park ◽  
Hiroyuki Horiuchi ◽  
Cher Won Hwang ◽  
Wan Hae Yeh ◽  
Akinori Ohta ◽  
...  
Keyword(s):  
Rice Blast ◽  
Rice Blast Fungus ◽  
Pyricularia Oryzae ◽  
Chitin Synthase ◽  
Class V ◽  
Myosin Motor ◽  
Blast Fungus

scholarly journals The class V myosin motor protein, Myo2, plays a major role in mitochondrial motility in Saccharomyces cerevisiae

2008 ◽  
Vol 181 (1) ◽  
pp. 119-130 ◽  
Author(s):  
Katrin Altmann ◽  
Martina Frank ◽  
Daniel Neumann ◽  
Stefan Jakobs ◽  
Benedikt Westermann
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Actin Cytoskeleton ◽  
Molecular Mechanisms ◽  
Budding Yeast ◽  
Motor Protein ◽  
Mitochondrial Morphology ◽  
Direct Role ◽  
Class V ◽  
Myosin Motor ◽  
Mitochondrial Motility

The actin cytoskeleton is essential for polarized, bud-directed movement of cellular membranes in Saccharomyces cerevisiae and thus ensures accurate inheritance of organelles during cell division. Also, mitochondrial distribution and inheritance depend on the actin cytoskeleton, though the precise molecular mechanisms are unknown. Here, we establish the class V myosin motor protein, Myo2, as an important mediator of mitochondrial motility in budding yeast. We found that mutants with abnormal expression levels of Myo2 or its associated light chain, Mlc1, exhibit aberrant mitochondrial morphology and loss of mitochondrial DNA. Specific mutations in the globular tail of Myo2 lead to aggregation of mitochondria in the mother cell. Isolated mitochondria lacking functional Myo2 are severely impaired in their capacity to bind to actin filaments in vitro. Time-resolved fluorescence microscopy revealed a block of bud-directed anterograde mitochondrial movement in cargo binding–defective myo2 mutant cells. We conclude that Myo2 plays an important and direct role for mitochondrial motility and inheritance in budding yeast.

scholarly journals Polarization of cell growth in yeast

2000 ◽  
Vol 113 (4) ◽  
pp. 571-585 ◽  
Author(s):  
D. Pruyne ◽  
A. Bretscher
Keyword(s):  
Actin Cytoskeleton ◽  
Structural Basis ◽  
Cell Cortex ◽  
Cortical Actin ◽  
Class V ◽  
Precise Control ◽  
Dependent Protein ◽  
Actin Cables ◽  
Protein Kinase Signaling ◽  
Structural Determinant

The actin cytoskeleton provides the structural basis for cell polarity in Saccharomyces cerevisiae as well as most other eukaryotes. In Part I of this two-part commentary, presented in the previous issue of Journal of Cell Science, we discussed the basis by which yeast establishes and maintains different states of polarity through Ρ GTPases and cyclin-dependent protein kinase signaling. Here we discuss how, in response to those signals, the actin cytoskeleton guides growth of the yeast cell. A polarized array of actin cables at the cell cortex is the primary structural determinant of polarity. Motors such as class V myosins use this array to transport secretory vesicles, mRNA and organelles towards growth sites, where they are anchored by a cap of cytoskeletal and regulatory proteins. Cortical actin patches enhance and maintain this polarity, probably through endocytic recycling, which allows reuse of materials and prevents continued growth at old sites. The dynamic arrangement of targeting and recycling provides flexibility for the precise control of morphogenesis.

scholarly journals Identification and Characterization of a CandidateWolbachia pipientisType IV Effector That Interacts with the Actin Cytoskeleton

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Kathy B. Sheehan ◽  
MaryAnn Martin ◽  
Cammie F. Lesser ◽  
Ralph R. Isberg ◽  
Irene L. G. Newton
Keyword(s):  
Actin Cytoskeleton ◽  
Cell Biology ◽  
Direct Interaction ◽  
Growth Defect ◽  
Rhodamine Phalloidin ◽  
Wolbachia Pipientis ◽  
Persistent Infections ◽  
Host Development

ABSTRACTMany bacteria live as intracellular symbionts, causing persistent infections within insects. One extraordinarily common infection is that ofWolbachia pipientis, which infects 40% of insect species and induces reproductive effects. The bacteria are passed from generation to generation both vertically (through the oocyte) and horizontally (by environmental transmission). Maintenance of the infection withinDrosophila melanogasteris sensitive to the regulation of actin, asWolbachiainefficiently colonizes strains hemizygous for the profilin or villin genes. Therefore, we hypothesized thatWolbachiamust depend on the host actin cytoskeleton. In this study, we identify and characterize aWolbachiaprotein (WD0830) that is predicted to be secreted by the bacterial parasite. Expression of WD0830 in a model eukaryote (the yeastSaccharomyces cerevisiae) induces a growth defect associated with the appearance of aberrant, filamentous structures which colocalize with rhodamine-phalloidin-stained actin. Purified WD0830 bundles actinin vitroand cosediments with actin filaments, suggesting a direct interaction of the two proteins. We characterized the expression of WD0830 throughoutDrosophiladevelopment and found it to be upregulated in third-instar larvae, peaking in early pupation, during the critical formation of adult tissues, including the reproductive system. In transgenic flies, heterologously expressed WD0830 localizes to the developing oocyte. Additionally, overexpression of WD0830 results in increasedWolbachiatiters in whole flies, in stage 9 and 10 oocytes, and in embryos, compared to controls, suggesting that the protein may facilitateWolbachia’s replication or transmission. Therefore, this candidate secreted effector may play a role inWolbachia’s infection of and persistence within host niches.IMPORTANCEThe obligate intracellularWolbachia pipientisis a ubiquitous alphaproteobacterial symbiont of arthropods and nematodes and is related to the rickettsial pathogensEhrlichiaspp. andAnaplasmaspp. Studies ofWolbachiacell biology suggest that this bacterium relies on host actin for efficient proliferation and transmission between generations. Here, we identified and characterized aWolbachiaprotein that localizes to and manipulates the eukaryotic actin cytoskeleton, is expressed byWolbachiaduring host development, and altersWolbachiatiters and localization in transgenic fruit flies. We hypothesize that WD0830 may be utilized by the bacterium to facilitate replication in or invasion of different niches during host development.

scholarly journals ChsVb, a Class VII Chitin Synthase Involved in Septation, Is Critical for Pathogenicity in Fusarium oxysporum

2007 ◽  
Vol 7 (1) ◽  
pp. 112-121 ◽  
Author(s):  
Magdalena Martín-Urdíroz ◽  
M. Isabel G. Roncero ◽  
José Antonio González-Reyes ◽  
Carmen Ruiz-Roldán
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Tomato Fruit ◽  
Infection Process ◽  
Chitin Synthase ◽  
Fungal Cell ◽  
Myosin Motor ◽  
Cell Wall Assembly ◽  
Chitin Synthases ◽  
Wall Assembly

ABSTRACT A new myosin motor-like chitin synthase gene, chsVb, has been identified in the vascular wilt fungus Fusarium oxysporum f. sp. lycopersici. Phylogenetic analysis of the deduced amino acid sequence of the chsVb chitin synthase 2 domain (CS2) revealed that ChsVb belongs to class VII chitin synthases. The ChsVb myosin motor-like domain (MMD) is shorter than the MMD of class V chitin synthases and does not contain typical ATP-binding motifs. Targeted disrupted single (ΔchsVb) and double (ΔchsV ΔchsVb) mutants were unable to infect and colonize tomato plants or grow invasively on tomato fruit tissue. These strains were hypersensitive to compounds that interfere with fungal cell wall assembly, produced lemon-like shaped conidia, and showed swollen balloon-like structures in hyphal subapical regions, thickened walls, aberrant septa, and intrahyphal hyphae. Our results suggest that the chsVb gene is likely to function in polarized growth and confirm the critical importance of cell wall integrity in the complex infection process of this fungus.

Characterization of chitin and chitin synthase from the cellulosic cell wall fungusSaprolegnia monoi¨ca

1992 ◽  
Vol 16 (1) ◽  
pp. 8-21 ◽  
Author(s):  
Vincent Bulone ◽  
Henri Chanzy ◽  
Lucien Gay ◽  
Vincent Girard ◽  
Michel Fe`vre
Keyword(s):  
Cell Wall ◽  
Chitin Synthase
Sign in / Sign up

Export Citation Format

Share Document