An axon or nerve fiber is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons, such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. Axon dysfunction can be the cause of many inherited and acquired neurological disorders that affect both the peripheral and central neurons. Nerve fibers are classed into three types – group A nerve fibers, group B nerve fibers, and group C nerve fibers. Groups A and B are myelinated, and group C are unmyelinated. These groups include both sensory fibers and motor fibers. Another classification groups only the sensory fibers as Type I, Type II, Type III, and Type IV.
In cell biology, the spindle apparatus is the cytoskeletal structure of eukaryotic cells that forms during cell division to separate sister chromatids between daughter cells. It is referred to as the mitotic spindle during mitosis, a process that produces genetically identical daughter cells, or the meiotic spindle during meiosis, a process that produces gametes with half the number of chromosomes of the parent cell.
Dyneins are a family of cytoskeletal motor proteins that move along microtubules in cells. They convert the chemical energy stored in ATP to mechanical work. Dynein transports various cellular cargos, provides forces and displacements important in mitosis, and drives the beat of eukaryotic cilia and flagella. All of these functions rely on dynein's ability to move towards the minus-end of the microtubules, known as retrograde transport; thus, they are called "minus-end directed motors". In contrast, most kinesin motor proteins move toward the microtubules' plus-end, in what is called anterograde transport.
Axoplasm is the cytoplasm within the axon of a neuron. For some neuronal types this can be more than 99% of the total cytoplasm.
The phragmoplast is a plant cell specific structure that forms during late cytokinesis. It serves as a scaffold for cell plate assembly and subsequent formation of a new cell wall separating the two daughter cells. The phragmoplast can only be observed in Phragmoplastophyta, a clade that includes the Coleochaetophyceae, Zygnematophyceae, Mesotaeniaceae, and Embryophyta. Some algae use another type of microtubule array, a phycoplast, during cytokinesis.
Motor proteins are a class of molecular motors that can move along the cytoplasm of cells. They convert chemical energy into mechanical work by the hydrolysis of ATP. Flagellar rotation, however, is powered by a proton pump.
Aurora kinase A also known as serine/threonine-protein kinase 6 is an enzyme that in humans is encoded by the AURKA gene.
In cell biology, microtubule nucleation is the event that initiates de novo formation of microtubules (MTs). These filaments of the cytoskeleton typically form through polymerization of α- and β-tubulin dimers, the basic building blocks of the microtubule, which initially interact to nucleate a seed from which the filament elongates.
Monastrol is a cell-permeable small molecule inhibitor discovered by Thomas U. Mayer in the lab of Tim Mitchison. Monastrol was shown to inhibit the kinesin-5, a motor protein important for spindle bipolarity.
Kinesin-like protein KIF23 is a protein that in humans is encoded by the KIF23 gene.
Kinesin family member 5B (KIF5B) is a protein that in humans is encoded by the KIF5B gene. It is part of the kinesin family of motor proteins.
Kinesin-like protein KIF2C is a protein that in humans is encoded by the KIF2C gene.
Protein Regulator of cytokinesis 1 (PRC1) is a protein that in humans is encoded by the PRC1 gene and is involved in cytokinesis.
Kinesin-like protein KIFC1 is a protein that in humans is encoded by the KIFC1 gene.
KIF1-binding protein, also known as Kinesin binding protein(KBP), is a protein that in humans is encoded by the KIAA1279 gene. The interaction of KBP with Kif15 is necessary for the localization of Kif15 to the microtubule plus-end at the spindle equator. Interaction between Kif15 and KBP is essential for the perfect alignment of chromosomes at the metaphase plate, and any defect in their interaction leads to delay in chromosomal alignment during mitosis. Anything that perturb the interaction of KBP and Kif15 can block the cells at mitosis, and hence it can be therapeutically used to control Kif15 upregulated cancer cells.
Kinesin-like protein KIF2A is a protein that in humans is encoded by the KIF2A gene. In mice, KIF2A is essential for proper neurogenesis and deficiency of KIF2A in mature neurons results in the loss of those neurons.
Kinesin-like protein KIF1A, also known as axonal transporter of synaptic vesicles or microtubule-based motor KIF1A, is a protein that in humans is encoded by the KIF1A gene.
Kinesin-like protein KIF11 is a molecular motor protein that is essential in mitosis. In humans it is coded for by the gene KIF11. Kinesin-like protein KIF11 is a member of the kinesin superfamily, which are nanomotors that move along microtubule tracks in the cell. Named from studies in the early days of discovery, it is also known as Kinesin-5, or as BimC, Eg5 or N-2, based on the founding members of this kinesin family.
Neurotubules are microtubules found in neurons in nervous tissues. Along with neurofilaments and microfilaments, they form the cytoskeleton of neurons. Neurotubules are undivided hollow cylinders that are made up of tubulin protein polymers and arrays parallel to the plasma membrane in neurons. Neurotubules have an outer diameter of about 23 nm and an inner diameter, also known as the central core, of about 12 nm. The wall of the neurotubules is about 5 nm in width. There is a non-opaque clear zone surrounding the neurotubule and it is about 40 nm in diameter. Like microtubules, neurotubules are greatly dynamic and the length of them can be adjusted by polymerization and depolymerization of tubulin.
Casper Hoogenraad is a Dutch Cell Biologist who specializes in molecular neuroscience. The focus of his research is the basic molecular and cellular mechanisms that regulate the development and function of the brain. As of January 2020, he serves as Vice President of Neuroscience at Genentech Research and Early Development.
