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Microtubule Nucleation
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. Microtubule nucleation occurs spontaneously ''in vitro'', with solutions of purified tubulin giving rise to full-length polymers. The tubulin dimers that make up the polymers have an intrinsic capacity to self-aggregate and assemble into cylindrical tubes, provided there is an adequate supply of GTP. The kinetics barriers of such a process, however, mean that the rate at which microtubules spontaneously nucleate is relatively low. Role of γ-tubulin and the γ-tubulin ring complex (γ-TuRC) ''In vivo'', cells get around this kinetic barrier by using various proteins to aid microtubule nucleation. The primary pathway by which microtubule nuclea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell Biology
Cell biology (also cellular biology or cytology) is a branch of biology that studies the structure, function, and behavior of cells. All living organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of organisms. Cell biology is the study of the structural and functional units of cells. Cell biology encompasses both prokaryotic and eukaryotic cells and has many subtopics which may include the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition. The study of cells is performed using several microscopy techniques, cell culture, and cell fractionation. These have allowed for and are currently being used for discoveries and research pertaining to how cells function, ultimately giving insight into understanding larger organisms. Knowing the components of cells and how cells work is fundamental to all biological sciences while also being essential for research in biomedical fiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitosis
Mitosis () is a part of the cell cycle in eukaryote, eukaryotic cells in which replicated chromosomes are separated into two new Cell nucleus, nuclei. Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the total number of chromosomes is maintained. Mitosis is preceded by the S phase of interphase (during which DNA replication occurs) and is followed by telophase and cytokinesis, which divide the cytoplasm, organelles, and cell membrane of one cell into two new cell (biology), cells containing roughly equal shares of these cellular components. The different stages of mitosis altogether define the mitotic phase (M phase) of a cell cycle—the cell division, division of the mother cell into two daughter cells genetically identical to each other. The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next. These stages are preprophase (specific to plant ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TPX2
Targeting protein for Xklp2 is a protein that in humans is encoded by the ''TPX2'' gene. It is one of the many spindle assembly factors that play a key role in inducing microtubule assembly and growth during M phase. Key domains of TPX2 TPX2 has been reported to have two NLS-containing domains that mediate its localization to microtubules; one in the amino-terminal domain, and the other in the carboxy-terminal domain. In addition to an NLS, the carboxy-terminal domain of TPX2 consists of tandem repeats that cover over two-thirds of the protein and are computationally predicted to consist of predominantly alpha-helical content. This region can be further divided into five clusters of conserved residues separated by unstructured regions: α3-7. α3-6 all contain a central α-helical region that is followed by a characteristic "FKARP" motif. α7 is longer and exhibits a long α-helical stretch that is computationally predicted to form a coiled coil. Lastly, the final 35 amino acids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila
''Drosophila'' (), from Ancient Greek δρόσος (''drósos''), meaning "dew", and φίλος (''phílos''), meaning "loving", is a genus of fly, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies (sometimes referred to as "true fruit flies"); tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly. One species of ''Drosophila'' in particular, ''Drosophila melanogaster'', has been heavily used in research in genetics and is a common model organism in developmental biology. The terms "fruit fly" and "''Drosophila''" are often used synonymously with ''D. melanogaster'' in modern biological literatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Internal Reflection Fluorescence Microscope
A total internal reflection fluorescence microscope (TIRFM) is a type of microscope with which a thin region of a specimen, usually less than 200 nanometers can be observed. TIRFM is an imaging modality which uses the excitation of fluorescent cells in a thin optical specimen section that is supported on a glass slide. The technique is based on the principle that when excitation light is totally internally reflected in a transparent solid coverglass at its interface with a liquid medium, an electromagnetic field, also known as an evanescent wave, is generated at the solid-liquid interface with the same frequency as the excitation light. The intensity of the evanescent wave exponentially decays with distance from the surface of the solid so that only fluorescent molecules within a few hundred nanometers of the solid are efficiently excited. Two-dimensional images of the fluorescence can then be obtained, although there are also mechanisms in which three-dimensional information on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HAUS3
HAUS augmin-like complex subunit 3 is a protein that in humans is encoded by the ''HAUS3'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei .... References Further reading * * * {{gene-4-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microtubule-associated Protein
In cell biology, microtubule-associated proteins (MAPs) are proteins that interact with the microtubules of the cellular cytoskeleton. MAPs are integral to the stability of the cell and its internal structures and the transport of components within the cell. Function MAPs bind to the tubulin subunits that make up microtubules to regulate their stability. A large variety of MAPs have been identified in many different cell types, and they have been found to carry out a wide range of functions. These include both stabilizing and destabilizing microtubules, guiding microtubules towards specific cellular locations, cross-linking microtubules and mediating the interactions of microtubules with other proteins in the cell. Within the cell, MAPs bind directly to the tubulin dimers of microtubules. This binding can occur with either polymerized or depolymerized tubulin, and in most cases leads to the stabilization of microtubule structure, further encouraging polymerization. Usually, it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cofilin
ADF/cofilin is a family of actin-binding proteins associated with the rapid depolymerization of Actin, actin microfilaments that give actin its characteristic dynamic instability. This dynamic instability is central to actin's role in muscle contraction, cell motility and transcription regulation. Three highly conserved and highly (70%-82%) identical genes belonging to this family have been described in humans and mice: * CFL1, coding for cofilin 1 (non-muscle, or n-cofilin) * CFL2 (gene), CFL2, coding for cofilin 2 (found in muscle: m-cofilin) * Destrin, DSTN, coding for destrin, also known as ADF or actin depolymerizing factor Actin-binding proteins regulate assembly and disassembly of actin filaments.Cooper, G. M. and R. E. Hausman. ''The Cell: A Molecular Approach,'' 3rd ed. Washington DC: ASM Press 2004 pp.436-440. Cofilin, a member of the ADF/cofilin family is actually a protein with 70% sequence identity to destrin, making it part of the ADF/cofilin family of small ADP-bind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Katanin
Katanin is a microtubule-severing AAA protein. It is named after the Japanese sword called a katana. Katanin is a heterodimeric protein first discovered in sea urchins. It contains a 60 kDa ATPase subunit, encoded by '' KATNA1'', which functions to sever microtubules. This subunit requires ATP and the presence of microtubules for activation. The second 80 kDA subunit, encoded by '' KATNB1'', regulates the activity of the ATPase and localizes the protein to centrosomes. Electron microscopy shows that katanin forms 14–16 nm rings in its active oligomerized state on the walls of microtubules (although not ''around'' the microtubule). Mechanism and regulation of microtubule length Structural analysis using electron microscopy has revealed that microtubule protofilaments change from a straight to a curved conformation upon GTP hydrolysis of β-tubulin. However, when these protofilaments are part of a polymerized microtubule, the stabilizing interactions created by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CAMSAP3
Calmodulin-regulated spectrin-associated protein family member 3 (CAMSAP3) is a human protein encoded by the gene CAMSAP3. The protein is commonly referred to as Nezha. Function CAMSAP3 acts as a minus-end anchor of microtubules, and binds to them through its CKK domain. In epithelial cells Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ..., it anchors microtubules to the apical cortex, causing them to grow in an apical-to-basal direction. This gives the epithelial cells their rectangular shape. In other species In early mouse embryogenesis, the interphase bridge linking sister cells is enriched with CAMSAP3. See also * CAMSAP1 * CAMSAP2 References {{Cytoskeletal proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelium
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of many internal organs, the corresponding inner surfaces of body cavities, and the inner surfaces of blood vessels. Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. These tissues also lack blood or lymph supply. The tissue is supplied by nerves. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either simple squamous, simple columnar, or simple cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axon
An axon (from Greek ἄξων ''áxōn'', axis) or nerve fiber (or nerve fibre: see American and British English spelling differences#-re, -er, spelling differences) is a long, slender cellular extensions, projection of a nerve cell, or neuron, in Vertebrate, vertebrates, that typically conducts electrical impulses known as action potentials away from the Soma (biology), nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands. In certain sensory neurons (pseudounipolar neurons), such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the peripheral nervous system, 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 nervous system, peripheral and Central nervous system, central ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
