Myosin motors at neuronal synapses: drivers of membrane transport and actin dynamics

2013 ◽  
Vol 14 (4) ◽  
pp. 233-247 ◽  
Author(s):  
Matthias Kneussel ◽  
Wolfgang Wagner
Keyword(s):  
Membrane Transport ◽  
Actin Dynamics ◽  
Neuronal Synapses ◽  
Myosin Motors

scholarly journals Myosin 1b is an actin depolymerase

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Julien Pernier ◽  
Remy Kusters ◽  
Hugo Bousquet ◽  
Thibaut Lagny ◽  
Antoine Morchain ◽  
...  
Keyword(s):  
Myosin Ii ◽  
Actin Dynamics ◽  
Myosin Motor ◽  
Actin Depolymerization ◽  
Cellular Processes ◽  
Myosin Motors ◽  
Singular Interactions ◽  
Sliding Motility

AbstractThe regulation of actin dynamics is essential for various cellular processes. Former evidence suggests a correlation between the function of non-conventional myosin motors and actin dynamics. Here we investigate the contribution of myosin 1b to actin dynamics using sliding motility assays. We observe that sliding on myosin 1b immobilized or bound to a fluid bilayer enhances actin depolymerization at the barbed end, while sliding on myosin II, although 5 times faster, has no effect. This work reveals a non-conventional myosin motor as another type of depolymerase and points to its singular interactions with the actin barbed end.

scholarly journals A role for talin in presynaptic function

2004 ◽  
Vol 167 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Jennifer R. Morgan ◽  
Gilbert Di Paolo ◽  
Hauke Werner ◽  
Valentina A. Shchedrina ◽  
Marc Pypaert ◽  
...  
Keyword(s):  
Actin Dynamics ◽  
Coated Pits ◽  
Dramatic Decrease ◽  
Functional Link ◽  
Neuronal Synapses ◽  
Presynaptic Function ◽  
Synaptic Structure ◽  
Phosphatidylinositol 4 ◽  
Insight Into

Talin, an adaptor between integrin and the actin cytoskeleton at sites of cell adhesion, was recently found to be present at neuronal synapses, where its function remains unknown. Talin interacts with phosphatidylinositol-(4)-phosphate 5-kinase type Iγ, the major phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P2]–synthesizing enzyme in brain. To gain insight into the synaptic role of talin, we microinjected into the large lamprey axons reagents that compete the talin–PIP kinase interaction and then examined their effects on synaptic structure. A dramatic decrease of synaptic actin and an impairment of clathrin-mediated synaptic vesicle endocytosis were observed. The endocytic defect included an accumulation of clathrin-coated pits with wide necks, as previously observed after perturbing actin at these synapses. Thus, the interaction of PIP kinase with talin in presynaptic compartments provides a mechanism to coordinate PI(4,5)P2 synthesis, actin dynamics, and endocytosis, and further supports a functional link between actin and clathrin-mediated endocytosis.

scholarly journals Diverse functions of myosin VI in spermiogenesis

2021 ◽  
Author(s):  
Przemysław Zakrzewski ◽  
Marta Lenartowska ◽  
Folma Buss
Keyword(s):  
Adaptor Proteins ◽  
Actin Dynamics ◽  
Actin Binding ◽  
Animal Cells ◽  
C Elegans ◽  
Cellular Processes ◽  
Sperm Development ◽  
Membrane Compartments ◽  
Myosin Motors ◽  
The Many

AbstractSpermiogenesis is the final stage of spermatogenesis, a differentiation process during which unpolarized spermatids undergo excessive remodeling that results in the formation of sperm. The actin cytoskeleton and associated actin-binding proteins play crucial roles during this process regulating organelle or vesicle delivery/segregation and forming unique testicular structures involved in spermatid remodeling. In addition, several myosin motor proteins including MYO6 generate force and movement during sperm differentiation. MYO6 is highly unusual as it moves towards the minus end of actin filaments in the opposite direction to other myosin motors. This specialized feature of MYO6 may explain the many proposed functions of this myosin in a wide array of cellular processes in animal cells, including endocytosis, secretion, stabilization of the Golgi complex, and regulation of actin dynamics. These diverse roles of MYO6 are mediated by a range of specialized cargo-adaptor proteins that link this myosin to distinct cellular compartments and processes. During sperm development in a number of different organisms, MYO6 carries out pivotal functions. In Drosophila, the MYO6 ortholog regulates actin reorganization during spermatid individualization and male KO flies are sterile. In C. elegans, the MYO6 ortholog mediates asymmetric segregation of cytosolic material and spermatid budding through cytokinesis, whereas in mice, this myosin regulates assembly of highly specialized actin-rich structures and formation of membrane compartments to allow the formation of fully differentiated sperm. In this review, we will present an overview and compare the diverse function of MYO6 in the specialized adaptations of spermiogenesis in flies, worms, and mammals.

scholarly journals Gq-mediated calcium dynamics and membrane tension modulate neurite plasticity

2019 ◽  
Author(s):  
Katherine M. Pearce ◽  
Miriam Bell ◽  
Will H. Linthicum ◽  
Qi Wen ◽  
Jagan Srinivasan ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Neural Circuit ◽  
Actin Dynamics ◽  
Membrane Tension ◽  
C Elegans ◽  
Neurite Retraction ◽  
Neuronal Synapses ◽  
Spontaneous Neuronal Activity ◽  
Cytoskeletal Elements ◽  
Circuit Formation

AbstractThe formation and disruption of synaptic connections during development is a fundamental step in neural circuit formation. Subneuronal structures such as neurites are known to be sensitive to the level of spontaneous neuronal activity but the specifics of how neurotransmitter-induced calcium activity regulates neurite homeostasis are not yet fully understood. In response to stimulation by neurotransmitters such as acetylcholine, calcium responses in cells are mediated the Gαq/phospholipase Cβ (PLCβ)/ phosphatidylinositol 4,5 bisphosphate (PI(4, 5)P2) signaling pathway. Here, we show that prolonged Gαq stimulation results in the retraction of neurites in PC12 cells and rupture of neuronal synapses by modulating membrane tension. To understand the underlying cause, we dissected the behavior of individual components of the Gαq/PLCβ/PI(4, 5)P2 pathway during retraction, and correlated these to the retraction of the membrane and cytoskeletal elements impacted by calcium signaling. We developed a mathematical model that combines biochemical signaling with membrane tension and cytoskeletal mechanics, to show how signaling events are coupled to retraction velocity, membrane tension and actin dynamics. The coupling between calcium and neurite retraction is shown to be operative in the C. elegans nervous system. This study uncovers a novel mechanochemical connection between the Gαq/PLCβ/(PI(4, 5)P2 pathway that couples calcium responses with neural plasticity.

scholarly journals A new actin depolymerase: a Myosin 1 motor

2018 ◽  
Author(s):  
Julien Pernier ◽  
Remy Kusters ◽  
Hugo Bousquet ◽  
Thibaut Lagny ◽  
Antoine Morchain ◽  
...  
Keyword(s):  
Myosin Ii ◽  
Actin Dynamics ◽  
Myosin Motor ◽  
Actin Depolymerization ◽  
Cellular Processes ◽  
New Type ◽  
Myosin Motors ◽  
Singular Interactions ◽  
Sliding Motility

AbstractThe regulation of actin dynamics is essential for various cellular processes. Former evidence suggests a correlation between the function of non-conventional myosin motors and actin dynamics. We investigate the contribution of myosin1b to actin dynamics using sliding motility assays. We observe that sliding on myosin1b immobilized or bound to a fluid bilayer enhances actin depolymerization at the barbed end, while sliding on myosin II, although 5 times faster, has no effect. This work reveals a non-conventional myosin motor as a new type of depolymerase and points to its singular interactions with the actin barbed end.

Astrocytes in health and disease

2007 ◽  
Vol 148 (15) ◽  
pp. 697-702 ◽  
Author(s):  
Marianna Murányi ◽  
Zsombor Lacza
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Free Radicals ◽  
Molecular Mechanisms ◽  
Neuronal Dysfunction ◽  
Supporting Cells ◽  
Neuronal Synapses ◽  
Health And Disease ◽  
Novel Targets ◽  
Therapeutic Tools

It is now known that astrocytes are not merely supporting cells but they also play an important role in neuronal funcions. Astrocytes tightly ensheat neuronal synapses and regulate the excitation of neurons by uptaking neurotransmitters; reglulate the cerebral blood flow, cerebral fluid volume and extracellular concentrations of ions. They also supply fuel in the form of lactate and provide free radical scavangers such as glutathione for active neurons. These facts indicate that impaired function of astrocytes may lead to neuronal dysfunction. After brain injury (stroke, trauma or tumors) astrocytes are swollen and release active molecules such as glutamate or free radicals resulting in neuronal dysfunction. Thus, investigation of the molecular mechanisms of astrocyte function may reveal novel targets for the development of therapeutic tools in neuronal diseases.

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