We show that the actin nucleation factor SCAR/WAVE is strongly activated during Dictyostelium cytokinesis. (biologists.com)
We demonstrate that SCAR activity is essential to drive myosin-II-independent cytokinesis, and stabilises the furrow, ensuring symmetrical division. (biologists.com)
Wang Y., Steimle P.A. , Ren Y., Ross C.A., Robinson D.N., Egelhoff T.T., Sesaki H., Iijima M. Dictyostelium huntingtin controls chemotaxis and cytokinesis through the regulation of myosin II phosphorylation. (uncg.edu)
Actin filaments4
Presumably this is so the myosins may interact, via their tails, with a large number of different cargoes, while the goal in each case - to move along actin filaments - remains the same and therefore requires the same machinery in the motor. (wikipedia.org)
These differences in shape also determine the speed at which myosins can move along actin filaments. (wikipedia.org)
BACKGROUND: Myosins are motors that use energy supplied by ATP to travel along actin filaments. (embl.de)
To this end, I use the social amoeba, Dictyostelium discoideum , as a model system for examining the molecular pathways regulating the ability of myosin II to mediate contraction of actin filaments in the highly dynamic context of a nonmuscle cell. (uncg.edu)
Phosphorylation3
Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by Dictyostelium myosin heavy chain kinase B. (2010) BMC Res Notes 3(1):56. (uncg.edu)
Quantitation of the distribution and flux of a mutant myosin-II that is defective in phosphorylation-dependent thick filament disassembly confirms that heavy chain phosphorylation regulates normal recruitment to the furrow cortex. (biomedcentral.com)
The analysis indicates that myosin-II flux through the cleavage furrow cortex is regulated by thick filament phosphorylation. (biomedcentral.com)
Unconventional myosins3
These new myosins were collectively termed "unconventional myosins" and have been found in many tissues other than muscle. (wikipedia.org)
The unconventional myosins also have divergent tail domains, suggesting unique functions. (wikipedia.org)
In the past few years, this premise has been supported by genetic evidence that has shown that unconventional myosins are essential for the proper functioning of neurons, retina and the sensory cells of the inner ear. (embl.de)
Proteins7
Myosins (/ˈmaɪəsɪn, -oʊ-/) are a superfamily of motor proteins best known for their roles in muscle contraction and in a wide range of other motility processes in eukaryotes. (wikipedia.org)
The neck domain can also serve as a binding site for myosin light chains which are distinct proteins that form part of a macromolecular complex and generally have regulatory functions. (wikipedia.org)
The nomenclature can therefore be somewhat confusing when attempting to compare the functions of myosin proteins within and between organisms. (wikipedia.org)
Similar filament-forming myosin proteins were found in cardiac muscle, smooth muscle, and nonmuscle cells. (wikipedia.org)
However, beginning in the 1970s, researchers began to discover new myosin genes in simple eukaryotes encoding proteins that acted as monomers and were therefore entitled Class I myosins. (wikipedia.org)
Owing to subtle but potentially crucial structural and functional differences between calmodulin (CaM) of different species, the biochemical study of low-affinity CaM-binding proteins from Dictyostelium discoideum likely necessitates the use of CaM from the same organism. (unige.ch)
The effectiveness of this methods is illustrated by the detection of potentially novel D. discoideum CaM-binding proteins and the preparatory purification of one of these proteins, a short tail myosin I. (unige.ch)
Isoforms1
Virtually all eukaryotic cells contain myosin isoforms. (wikipedia.org)
Amoeba1
The structure and function of myosin is globally conserved across species, to the extent that rabbit muscle myosin II will bind to actin from an amoeba. (wikipedia.org)
Filaments2
This protein makes up part of the sarcomere and forms macromolecular filaments composed of multiple myosin subunits. (wikipedia.org)
Myosin is a major component of thick filaments and exists as a hexamer of 2 heavy chains [ ( PUBMED:1939027 ) ], 2 alkali light chains, and 2 regulatory light chains. (embl.de)
Molecule3
The power stroke occurs at the release of phosphate from the myosin molecule after the ATP hydrolysis while myosin is tightly bound to actin. (wikipedia.org)
The release of the ADP molecule leads to the so-called rigor state of myosin. (wikipedia.org)
The binding of a new ATP molecule will release myosin from actin. (wikipedia.org)
Chains1
Three embryonic class II myosin heavy chains (MYHs) were cloned from the common carp ( Cyprinus carpio L.), MYH emb1 ,MYH emb2 and MYH emb3 . (biologists.com)
Biochemical2
Biochemical and physiological evidence has suggested that myosins, both conventional and unconventional, are critical for neurosensory activities. (embl.de)
A biochemical mechanism for the spatial regulation of myosin II filament disassembly. (uncg.edu)
Cardiac muscle1
Myosin-binding protein C stabilizes, but is not the sole determinant of SRX myosin in cardiac muscle. (tamu.edu)
Hydrolysis4
The head domain binds the filamentous actin, and uses ATP hydrolysis to generate force and to "walk" along the filament towards the barbed (+) end (with the exception of myosin VI, which moves towards the pointed (-) end). (wikipedia.org)
Multiple myosin II molecules generate force in skeletal muscle through a power stroke mechanism fuelled by the energy released from ATP hydrolysis. (wikipedia.org)
ATP hydrolysis within the myosin will cause it to bind to actin again to repeat the cycle. (wikipedia.org)
The structure of myosin is known, but the actin-binding site is not well defined, and the mechanisms by which actin activates ATP hydrolysis by myosin, and myosin moves relative to the actin filament, developing force, are not fully understood. (embl.de)
Cells4
The growing family of myosin motors and their role in neurons and sensory cells. (embl.de)
The best understood of these involves myosin-II-dependent constriction around the cell equator, but both Dictyostelium and mammalian cells also use a parallel, adhesion-dependent mechanism to generate furrows. (biologists.com)
We used direct morphometric characterization and laser-tracking microrheology to quantify cortical mechanical properties of wild-type and cortexillin-I and dynacortin mutant Dictyostelium cells. (johnshopkins.edu)
WD repeat domain of Dictyostelium myosin heavy chain kinase C functions in both substrate targeting and cellular localization. (uncg.edu)
The myosin-II in the furrow cortex, however, represents only 10% of the total cellular myosin-II. (biomedcentral.com)
Purification1
The present study describes the expression of D. discoideum CaM in Escherichia coli and its straightforward and rapid purification. (unige.ch)
Furrow3
The peak concentration of GFP-myosin-II in the furrow cortex is 1.8-fold higher than in the polar cortex and 2.0-fold higher than in the cytoplasm. (biomedcentral.com)
The cell may, therefore, regulate the amount of myosin-II sent to the furrow cortex in accordance with the amount needed there. (biomedcentral.com)
Further, the amount of myosin-II observed in the furrow cortex is in close agreement with the amount predicted to be required from a simple theoretical analysis. (biomedcentral.com)
Phylogenetic1
Previous phylogenetic analyses of the motor domain of myosins have identified up to twelve classes. (embl.de)
Tail3
Most myosin molecules are composed of a head, neck, and tail domain. (wikipedia.org)
The tail domain generally mediates interaction with cargo molecules and/or other myosin subunits. (wikipedia.org)
Analysis of the amino acid sequences of different myosins shows great variability among the tail domains, but strong conservation of head domain sequences. (wikipedia.org)
Consists2
Muscle contraction consists of a cyclical interaction between myosin and actin. (embl.de)
Here we report the first quantitative analysis of the distribution and flux of myosin-II, an essential element of the contractile ring. (biomedcentral.com)
Function3
Following the discovery in 1973 of enzymes with myosin-like function in Acanthamoeba castellanii, a global range of divergent myosin genes have been discovered throughout the realm of eukaryotes. (wikipedia.org)
Conservation within the myosin motor domain: implications for structure and function. (embl.de)
Linking Ras to myosin function: RasGEF Q, a Dictyostelium exchange factor for RasB, affects myosin II functions. (uncg.edu)
Contractile1
The contractile vacuoles in Dictyostelium represent a highly efficient acidic Ca 2+ -store that is required for cAMP-induced Ca 2+ -influx. (biomedcentral.com)
Head1
The three-dimensional structures of the truncated myosin head from Dictyostelium discoideum myosin II complexed with dinitrophenylaminoethyl-, dinitrophenylaminopropyl-, o-nitrophenylaminoethyl-, m-nitrophenylaminoethyl-, p-nitrophenylaminoethyl-, and o-nitrophenyl-N-methyl-aminoethyl-diphosphate.beryllium fluoride have been determined to better than 2.3-A resolution. (rcsb.org)
Analysis1
RESULTS: Our analysis indicates that there are at least thirteen myosin classes. (embl.de)
Similar2
The core of the myosin structure is similar in fold to that of kinesin. (embl.de)
Loss of SCAR in both Dictyostelium and Drosophila leads to a similar mitotic phenotype, with severe mitotic blebbing, indicating conserved functionality. (biologists.com)
Structure2
We set out to analyse the positions of conserved residues within this domain in detail, and relate the conserved residues to the myosin structure. (embl.de)
The crystal structure of the motor domain of Dictyostelium discoideum myosin‐IE, a monomeric unconventional myosin, was determined. (mpg.de)
Domain1
The orientation of the converter domain is ∼30° further up than in other myosin structures, indicating that MyoE can produce a larger power stroke by rotating its lever arm through a larger angle. (mpg.de)