Target type: cellularcomponent
A heterodimer of tubulins alpha and beta that constitutes the protomer for microtubule assembly. [ISBN:0716731363]
The tubulin complex is a fundamental component of eukaryotic cells, forming the building blocks of microtubules. Microtubules are dynamic, filamentous structures that play crucial roles in a wide array of cellular processes, including:
- **Cell division:** Microtubules form the spindle fibers that separate chromosomes during mitosis and meiosis, ensuring accurate distribution of genetic material to daughter cells.
- **Cell shape and structure:** Microtubules provide structural support to cells, maintaining their shape and contributing to the organization of intracellular organelles.
- **Intracellular transport:** Microtubules serve as tracks for motor proteins like kinesin and dynein, which transport vesicles, organelles, and other cargos throughout the cell.
- **Cilia and flagella:** Microtubules are the core components of cilia and flagella, hair-like structures that enable movement and sensory functions in certain cells.
**Structure of the Tubulin Complex:**
The basic unit of a microtubule is a heterodimer composed of two tubulin proteins: alpha-tubulin and beta-tubulin. These proteins are highly conserved across eukaryotes and exhibit a globular shape. Each tubulin monomer binds a single molecule of GTP (guanosine triphosphate), which plays a vital role in microtubule dynamics.
Alpha-tubulin and beta-tubulin associate head-to-tail to form a dimer, with the alpha-tubulin subunit exposed at one end and the beta-tubulin subunit exposed at the other. These dimers then assemble into protofilaments, linear chains of tubulin dimers. Thirteen protofilaments associate laterally to create a hollow cylindrical structure, the microtubule.
**Microtubule Dynamics:**
Microtubules exhibit dynamic instability, a process characterized by periods of rapid growth (polymerization) and shrinkage (depolymerization). This dynamic behavior is essential for microtubule function and is regulated by factors such as GTP hydrolysis, tubulin concentration, and microtubule-associated proteins (MAPs).
**Microtubule-Associated Proteins (MAPs):**
MAPs are proteins that bind to microtubules and regulate their assembly, stability, and interactions with other cellular components. Different MAPs perform a variety of functions, including:
- **Stabilizing microtubules:** Some MAPs promote microtubule stability by cross-linking protofilaments or binding to the ends of microtubules.
- **Promoting microtubule dynamics:** Other MAPs can promote microtubule depolymerization or regulate the rate of polymerization.
- **Linking microtubules to other cellular structures:** MAPs can connect microtubules to organelles, membranes, and other cytoskeletal components.
**In summary, the tubulin complex is a vital structural and functional component of eukaryotic cells. Its dynamic nature, combined with the influence of MAPs, allows microtubules to perform a wide range of essential roles in cellular processes.**'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Microtubule-associated protein tau | A microtubule-associated protein tau that is encoded in the genome of human. [PRO:DAN] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| gentian violet | crystal violet cation : An iminium ion that is malachite green cation in which the hydrogen at the para- psition of the monosubstituted phenyl group is replaced by a dimethylamino group. | iminium ion | antibacterial agent; antifungal agent |
| lansoprazole | Lansoprazole: A 2,2,2-trifluoroethoxypyridyl derivative of timoprazole that is used in the therapy of STOMACH ULCERS and ZOLLINGER-ELLISON SYNDROME. The drug inhibits H(+)-K(+)-EXCHANGING ATPASE which is found in GASTRIC PARIETAL CELLS. Lansoprazole is a racemic mixture of (R)- and (S)-isomers. | benzimidazoles; pyridines; sulfoxide | anti-ulcer drug; EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor |
| 3,7-bis(dimethylamino)phenothiazin-5-ium | 3,7-bis(dimethylamino)phenothiazin-5-ium : An organic cation that is phenothiazin-5-ium substituted by dimethylamino groups at positions 3 and 7. The chloride salt is the histological dye 'methylene blue'. | organic cation | |
| aurin | aurin: structure | diarylmethane | |
| methylene blue | methylene blue : An organic chloride salt having 3,7-bis(dimethylamino)phenothiazin-5-ium as the counterion. A commonly used dye that also exhibits antioxidant, antimalarial, antidepressant and cardioprotective properties. Methylene Blue: A compound consisting of dark green crystals or crystalline powder, having a bronze-like luster. Solutions in water or alcohol have a deep blue color. Methylene blue is used as a bacteriologic stain and as an indicator. It inhibits GUANYLATE CYCLASE, and has been used to treat cyanide poisoning and to lower levels of METHEMOGLOBIN. | organic chloride salt | acid-base indicator; antidepressant; antimalarial; antimicrobial agent; antioxidant; cardioprotective agent; EC 1.4.3.4 (monoamine oxidase) inhibitor; EC 3.1.1.8 (cholinesterase) inhibitor; EC 4.6.1.2 (guanylate cyclase) inhibitor; fluorochrome; histological dye; neuroprotective agent; physical tracer |
| tolonium chloride | tolonium chloride : An organic chloride salt having 3-amino-7-(dimethylamino)-2-methylphenothiazin-5-ium (tolonium) as the counterion. It is a blue nuclear counterstain that can be used to demonstrate Nissl substance and is also useful for staining mast cell granules, both in metachromatic and orthochromatic techniques. Tolonium Chloride: A phenothiazine that has been used as a hemostatic, a biological stain, and a dye for wool and silk. Tolonium chloride has also been used as a diagnostic aid for oral and gastric neoplasms and in the identification of the parathyroid gland in thyroid surgery. | ||
| azure a | azure A : An organic chloride salt having 3-amino-7-(dimethylamino)phenothiazin-5-ium as the counterion. It is used in making azure eosin stains for blood smear staining. Azure A: RN given refers to chloride | ||
| thionine | thionine : An organic chloride salt composed of 3,7-diaminophenothiazin-5-ium and chloride ions in a 1:1 ratio. A strongly metachromatic dye, useful for the staining of acid mucopolysaccharides. It is also a common nuclear stain and can be used for the demonstration of Nissl substance in nerve cells of the CNS. thionine: do not confuse with the thionins which is a class of polypeptides; RN above is for the chloride; | ||
| epigallocatechin gallate | (-)-epigallocatechin 3-gallate : A gallate ester obtained by the formal condensation of gallic acid with the (3R)-hydroxy group of (-)-epigallocatechin. epigallocatechin gallate: a steroid 5alpha-reductase inhibitor and antimutagen in green tea (Camellia sinensis) | flavans; gallate ester; polyphenol | antineoplastic agent; antioxidant; apoptosis inducer; geroprotector; Hsp90 inhibitor; neuroprotective agent; plant metabolite |
| azure b | azure B : An organic chloride salt having 3-(dimethylamino)-7-(methylamino)phenothiazin-5-ium as the counterion. It is used in making azure eosin stains for blood smear staining and is an active metabolite of methylene blue. Azure B: RN given refers to chloride | ||
| epicatechin | (-)-epicatechin : A catechin with (2R,3R)-configuration. | catechin; polyphenol | antioxidant |
| curcumin | curcumin : A beta-diketone that is methane in which two of the hydrogens are substituted by feruloyl groups. A natural dyestuff found in the root of Curcuma longa. Curcumin: A yellow-orange dye obtained from tumeric, the powdered root of CURCUMA longa. It is used in the preparation of curcuma paper and the detection of boron. Curcumin appears to possess a spectrum of pharmacological properties, due primarily to its inhibitory effects on metabolic enzymes. | aromatic ether; beta-diketone; diarylheptanoid; enone; polyphenol | anti-inflammatory agent; antifungal agent; antineoplastic agent; biological pigment; contraceptive drug; dye; EC 1.1.1.205 (IMP dehydrogenase) inhibitor; EC 1.1.1.21 (aldehyde reductase) inhibitor; EC 1.1.1.25 (shikimate dehydrogenase) inhibitor; EC 1.6.5.2 [NAD(P)H dehydrogenase (quinone)] inhibitor; EC 1.8.1.9 (thioredoxin reductase) inhibitor; EC 2.7.10.2 (non-specific protein-tyrosine kinase) inhibitor; EC 3.5.1.98 (histone deacetylase) inhibitor; flavouring agent; food colouring; geroprotector; hepatoprotective agent; immunomodulator; iron chelator; ligand; lipoxygenase inhibitor; metabolite; neuroprotective agent; nutraceutical; radical scavenger |
| gossypetin | gossypetin : A hexahydroxyflavone having the hydroxy groups placed at the 3-, 3'-, 4'-, 5- 7- and 8-positions. gossypetin: inhibits activity of penicillinase enzyme in E coli | 7-hydroxyflavonol; hexahydroxyflavone | plant metabolite |
| myricetin | 7-hydroxyflavonol; hexahydroxyflavone | antineoplastic agent; antioxidant; cyclooxygenase 1 inhibitor; food component; geroprotector; hypoglycemic agent; plant metabolite | |
| su 4312 | SU4312 : A member of the class of oxindoles that is 3-methyleneoxindole in which one of the hydrogens of the methylene group has been replaced by a p-(dimethylamino)phenyl group. SU 4312 is a vascular endothelial growth factor (VEGF) receptor protein tyrosine kinase 1/2 and platelet derived growth factor (PDGF) receptor inhibitor. It also inhibits the neuronal nitric oxide synthase (NOS) and exhibits neuroprotection against NO-mediated neurotoxicity. | ||
| 2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole | |||
| cnb 001 | |||
| hydrazinocurcumin | hydrazinocurcumin : A pyrazole obtained by cyclocodensation of the two carbonyl groups of curcumin with hydrazine. hydrazinocurcumin: structure in first source | aromatic ether; olefinic compound; polyphenol; pyrazoles | angiogenesis modulating agent; antineoplastic agent; EC 2.3.1.48 (histone acetyltransferase) inhibitor; EC 2.7.11.1 (non-specific serine/threonine protein kinase) inhibitor |