CytoskeletonThe cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components, microfilaments, intermediate filaments and microtubules, and these are all capable of rapid growth or disassembly dependent on the cell's requirements.
Paclitaxel total synthesisPaclitaxel total synthesis in organic chemistry is a major ongoing research effort in the total synthesis of paclitaxel (Taxol). This diterpenoid is an important drug in the treatment of cancer but, also expensive because the compound is harvested from a scarce resource, namely the Pacific yew (Taxus brevifolia). Not only is the synthetic reproduction of the compound itself of great commercial and scientific importance, but it also opens the way to paclitaxel derivatives not found in nature but with greater potential.
Post-translational modificationPost-translational modification (PTM) is the covalent process of changing proteins following protein biosynthesis. PTMs may involve enzymes or occur spontaneously. Proteins are created by ribosomes translating mRNA into polypeptide chains, which may then change to form the mature protein product. PTMs are important components in cell signalling, as for example when prohormones are converted to hormones. Post-translational modifications can occur on the amino acid side chains or at the protein's C- or N- termini.
Aster (cell biology)An aster is a cellular structure shaped like a star, consisting of a centrosome and its associated microtubules during the early stages of mitosis in an animal cell. Asters do not form during mitosis in plants. Astral rays, composed of microtubules, radiate from the centrosphere and look like a cloud. Astral rays are one variant of microtubule which comes out of the centrosome; others include kinetochore microtubules and polar microtubules. During mitosis, there are five stages of cell division: Prophase, Prometaphase, Metaphase, Anaphase, and Telophase.
FilopodiaFilopodia (: filopodium) are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells. Within the lamellipodium, actin ribs are known as microspikes, and when they extend beyond the lamellipodia, they're known as filopodia. They contain microfilaments (also called actin filaments) cross-linked into bundles by actin-bundling proteins, such as fascin and fimbrin. Filopodia form focal adhesions with the substratum, linking them to the cell surface.
Natural productA natural product is a natural compound or substance produced by a living organism—that is, found in nature. In the broadest sense, natural products include any substance produced by life. Natural products can also be prepared by chemical synthesis (both semisynthesis and total synthesis) and have played a central role in the development of the field of organic chemistry by providing challenging synthetic targets.
ForminsFormins (formin homology proteins) are a group of proteins that are involved in the polymerization of actin and associate with the fast-growing end (barbed end) of actin filaments. Most formins are Rho-GTPase effector proteins. Formins regulate the actin and microtubule cytoskeleton and are involved in various cellular functions such as cell polarity, cytokinesis, cell migration and SRF transcriptional activity. Formins are multidomain proteins that interact with diverse signalling molecules and cytoskeletal proteins, although some formins have been assigned functions within the nucleus.
VimentinVimentin is a structural protein that in humans is encoded by the VIM gene. Its name comes from the Latin vimentum which refers to an array of flexible rods. Vimentin is a type III intermediate filament (IF) protein that is expressed in mesenchymal cells. IF proteins are found in all animal cells as well as bacteria. Intermediate filaments, along with tubulin-based microtubules and actin-based microfilaments, comprises the cytoskeleton.
Multiple myelomaMultiple myeloma (MM), also known as plasma cell myeloma and simply myeloma, is a cancer of plasma cells, a type of white blood cell that normally produces antibodies. Often, no symptoms are noticed initially. As it progresses, bone pain, anemia, kidney dysfunction, and infections may occur. Complications may include amyloidosis. The cause of multiple myeloma is unknown. Risk factors include obesity, radiation exposure, family history, age and certain chemicals. There is an increased risk of multiple myeloma in certain occupations.
KataninKatanin 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.
