scholarly journals 13 Plus 1: A 30-Year Perspective on Microtubule-Based Motility in Dictyostelium

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 528 ◽  
Author(s):  
Michael P. Koonce
Keyword(s):  
Actin Cytoskeleton ◽  
Dictyostelium Discoideum ◽  
Motor Proteins ◽  
Comprehensive Approach ◽  
Collective Actions ◽  
Complete Understanding ◽  
Cellular Dynamics ◽  
Individual Gene ◽  
Cytoplasmic Organization ◽  
Rough Draft

Individual gene analyses of microtubule-based motor proteins in Dictyostelium discoideum have provided a rough draft of its machinery for cytoplasmic organization and division. This review collates their activities and looks forward to what is next. A comprehensive approach that considers the collective actions of motors, how they balance rates and directions, and how they integrate with the actin cytoskeleton will be necessary for a complete understanding of cellular dynamics.

scholarly journals Myosins in Osteoclast Formation and Function

Biomolecules ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 157 ◽  
Author(s):  
Beth Lee
Keyword(s):  
Actin Cytoskeleton ◽  
Motor Proteins ◽  
Current Knowledge ◽  
Osteoclast Differentiation ◽  
Osteoclast Formation ◽  
Bone Modeling ◽  
Cell Type ◽  
And Function ◽  
Bone Modeling And Remodeling

Skeletal quantity and quality are determined by processes of bone modeling and remodeling, which are undertaken by cells that build and resorb bone as they respond to mechanical, hormonal, and other external and internal signals. As the sole bone resorptive cell type, osteoclasts possess a remarkably dynamic actin cytoskeleton that drives their function in this enterprise. Actin rearrangements guide osteoclasts’ capacity for precursor fusion during differentiation, for migration across bone surfaces and sensing of their composition, and for generation of unique actin superstructures required for the resorptive process. In this regard, it is not surprising that myosins, the superfamily of actin-based motor proteins, play key roles in osteoclast physiology. This review briefly summarizes current knowledge of the osteoclast actin cytoskeleton and describes myosins’ roles in osteoclast differentiation, migration, and actin superstructure patterning.

scholarly journals The Dictyostelium discoideum model system

2019 ◽  
Vol 63 (8-9-10) ◽  
pp. 317-320 ◽  
Author(s):  
Ricardo Escalante ◽  
Elena Cardenal-Muñoz
Keyword(s):  
Cell Motility ◽  
Dictyostelium Discoideum ◽  
Cell Biology ◽  
Model Organism ◽  
Opportunity To Learn ◽  
Model System ◽  
Special Issue ◽  
Complete Understanding ◽  
Single Model ◽  
Present Collection

When we set out to organize this Special Issue, we faced the difficult task of gathering together a large variety of topics with the unique commonality of having been studied in a single model organism, Dictyostelium discoideum. This apparent setback turned into a wonderful opportunity to learn about an organism as a whole, which provides a more complete understanding of life processes, their natural meaning and their changes during evolution. From studies dedicated almost exclusively to cell motility, differentiation and patterning, the versatility of D. discoideum has allowed in recent years the expansion of our knowledge to other areas, including cell biology and many others related to human diseases. The present collection of papers can be considered as a journey throughout the mechanisms of life, where D. discoideum acts as a very special tourist guide.

Transduction of the chemotactic signal to the actin cytoskeleton of Dictyostelium discoideum

1989 ◽  
Vol 136 (2) ◽  
pp. 517-525 ◽  
Author(s):  
Anne L. Hall ◽  
Vivien Warren ◽  
John Condeelis
Keyword(s):  
Actin Cytoskeleton ◽  
Dictyostelium Discoideum

scholarly journals How Phagocytic Cells Kill Different Bacteria: a Quantitative Analysis Using Dictyostelium discoideum

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tania Jauslin ◽  
Otmane Lamrabet ◽  
Xenia Crespo-Yañez ◽  
Anna Marchetti ◽  
Imen Ayadi ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Dictyostelium Discoideum ◽  
Human Body ◽  
Relative Importance ◽  
Phagocytic Cells ◽  
Bacterial Killing ◽  
Content Type ◽  
Individual Gene ◽  
Genetic Manipulations ◽  
High Degree

ABSTRACT Ingestion and killing of bacteria by phagocytic cells protect the human body against infections. While many mechanisms have been proposed to account for bacterial killing in phagosomes, their relative importance, redundancy, and specificity remain unclear. In this study, we used the Dictyostelium discoideum amoeba as a model phagocyte and quantified the requirement of 11 individual gene products, including nine putative effectors, for the killing of bacteria. This analysis revealed that radically different mechanisms are required to kill Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. AlyL, a lysozyme-like protein equipped with a distinct bacteriolytic region, plays a specific role in the intracellular killing of K. pneumoniae, with assistance from BpiC and Aoah, two lipopolysaccharide (LPS)-binding proteins. Rapid killing of E. coli and P. aeruginosa requires the presence of BpiC and of the NoxA NADPH oxidase. No single effector tested is essential for rapid killing of S. aureus or B. subtilis. Overall, our observations reveal an unsuspected degree of specificity in the elimination of bacteria in phagosomes. IMPORTANCE Phagocytic cells ingest and kill bacteria, a process essential for the defense of the human body against infections. Many potential killing mechanisms have been identified in phagocytic cells, including free radicals, toxic ions, enzymes, and permeabilizing peptides. Yet fundamental questions remain unanswered: what is the relative importance of these mechanisms, how redundant are they, and are different mechanisms used to kill different species of bacteria? We addressed these questions using Dictyostelium discoideum, a model phagocytic cell amenable to genetic manipulations and quantitative analysis. Our results reveal that vastly different mechanisms are required to kill different species of bacteria. This very high degree of specificity was unexpected and indicates that a lot remains to be discovered about how phagocytic cells eliminate bacteria.

scholarly journals Inactivation of Two Dictyostelium discoideum Genes, DdPIK1 and DdPIK2, Encoding Proteins Related to Mammalian Phosphatidylinositide 3-kinases, Results in Defects in Endocytosis, Lysosome to Postlysosome Transport, and Actin Cytoskeleton Organization

1997 ◽  
Vol 136 (6) ◽  
pp. 1271-1286 ◽  
Author(s):  
Greg Buczynski ◽  
Bryon Grove ◽  
Anson Nomura ◽  
Maurice Kleve ◽  
John Bush ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Dictyostelium Discoideum ◽  
Mutant Strain ◽  
Fluorescent Microscopy ◽  
Membrane Traffic ◽  
Fluid Phase ◽  
Cytoskeleton Organization ◽  
Actin Cytoskeleton Organization ◽  
Endosomal Pathway ◽  
Mutant Cells

Phosphatidylinositide 3-kinases (PI 3-kinases) have been implicated in controlling cell proliferation, actin cytoskeleton organization, and the regulation of vesicle trafficking between intracellular organelles. There are at least three genes in Dictyostelium discoideum, DdPIK1, DdPIK2, and DdPIK3, encoding proteins most closely related to the mammalian 110-kD PI-3 kinase in amino acid sequence within the kinase domain. A mutant disrupted in DdPIK1 and DdPIK2 (Δddpik1/ddpik2) grows slowly in liquid medium. Using FITC-dextran (FD) as a fluid phase marker, we determined that the mutant strain was impaired in pinocytosis but normal in phagocytosis of beads or bacteria. Microscopic and biochemical approaches indicated that the transport rate of fluid-phase from acidic lysosomes to non-acidic postlysosomal vacuoles was reduced in mutant cells resulting in a reduction in efflux of fluid phase. Mutant cells were also almost completely devoid of large postlysosomal vacuoles as determined by transmission EM. However, Δddpik1/ddpik2 cells functioned normally in the regulation of other membrane traffic. For instance, radiolabel pulse-chase experiments indicated that the transport rates along the secretory pathway and the sorting efficiency of the lysosomal enzyme α-mannosidase were normal in the mutant strain. Furthermore, the contractile vacuole network of membranes (probably connected to the endosomal pathway by membrane traffic) was functionally and morphologically normal in mutant cells. Light microscopy revealed that Δddpik1/ddpik2 cells appeared smaller and more irregularly shaped than wild-type cells; 1–3% of the mutant cells were also connected by a thin cytoplasmic bridge. Scanning EM indicated that the mutant cells contained numerous filopodia projecting laterally and vertically from the cell surface, and fluorescent microscopy indicated that these filopodia were enriched in F-actin which accumulated in a cortical pattern in control cells. Finally, Δddpik1/ddpik2 cells responded and moved more rapidly towards cAMP. Together, these results suggest that Dictyostelium DdPIK1 and DdPIK2 gene products regulate multiple steps in the endosomal pathway, and function in the regulation of cell shape and movement perhaps through changes in actin organization.

Probing cytoplasmic organization and the actin cytoskeleton of plant cells with optical tweezers

2010 ◽  
Vol 38 (3) ◽  
pp. 823-828 ◽  
Author(s):  
Tijs Ketelaar ◽  
Hannie S. van der Honing ◽  
Anne Mie C. Emons
Keyword(s):  
Actin Cytoskeleton ◽  
Physical Properties ◽  
Optical Tweezers ◽  
Intracellular Transport ◽  
Plant Cells ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Structural Basis ◽  
Actin Organization ◽  
Cytoplasmic Organization

In interphase plant cells, the actin cytoskeleton is essential for intracellular transport and organization. To fully understand how the actin cytoskeleton functions as the structural basis for cytoplasmic organization, both molecular and physical aspects of the actin organization have to be considered. In the present review, we discuss literature that gives an insight into how cytoplasmic organization is achieved and in which actin-binding proteins have been identified that play a role in this process. We discuss how physical properties of the actin cytoskeleton in the cytoplasm of live plant cells, such as deformability and elasticity, can be probed by using optical tweezers. This technique allows non-invasive manipulation of cytoplasmic organization. Optical tweezers, integrated in a confocal microscope, can be used to manipulate cytoplasmic organization while studying actin dynamics. By combining this with mutant studies and drug applications, insight can be obtained about how the physical properties of the actin cytoskeleton, and thus the cytoplasmic organization, are influenced by different cellular processes.

scholarly journals Myosin driven Actin Filament Sliding is Responsible for Endoplasmic Reticulum and Golgi Movement

2018 ◽  
Author(s):  
Joseph F McKenna ◽  
Stephen E D Webb ◽  
Verena Kriechbaumer ◽  
Chris Hawes
Keyword(s):  
Endoplasmic Reticulum ◽  
Actin Cytoskeleton ◽  
Actin Filament ◽  
Secretory Pathway ◽  
Motor Proteins ◽  
In Planta ◽  
Cell Dynamics ◽  
Myosin Motor ◽  
Golgi Bodies ◽  
Early Secretory Pathway

AbstractThe plant secretory pathway is responsible for the production of the majority of proteins and carbohydrates consumed on the planet. The early secretory pathway is composed of Golgi bodies and the endoplasmic reticulum (ER) and is highly mobile in plants with rapid remodelling of the ER network. The dynamics of the ER and Golgi bodies is driven by the actin cytoskeleton and myosin motor proteins play a key role in this. However, exactly how myosin motor proteins drive remodelling in plants is currently a contentious issue. Here, using a combination of live cell microscopy and over-expression of non-functional myosins we demonstrate that myosin motor proteins drive actin filament sliding and subsequently the dynamics of the secretory pathway.SummaryIn plants, the actin cytoskeleton and myosins are fundamental for normal dynamics of the endomembrane system and cytoplasmic streaming. We demonstrate that this is in part due to myosin driven sliding of actin filaments within a bundle. This generates, at least in part, the motive force required for cell dynamics in planta.

scholarly journals Active random forces can drive differential cellular positioning and enhance motor-driven transport

2020 ◽  
Vol 31 (20) ◽  
pp. 2283-2288
Author(s):  
Charles W. Wolgemuth ◽  
Sean X. Sun
Keyword(s):  
Actin Cytoskeleton ◽  
Motor Proteins ◽  
Random Forces

Random forces from motor proteins acting on the actin cytoskeleton are found to be able to drive size-based cellular positioning.

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