Biomaterial Database

Identification of the major 68,000-dalton protein of microtubule preparations as a 10-nm filament protein and its effects on microtubule assembly in vitro. 1979

M S Runge, and H W Detrich, and R C Williams

The major 68,000-dalton protein present in cycled microtubule preparations from bovine brain can be isolated in a rapidly sedimenting fraction consisting of filaments 10 nm in diameter. This 68,000-dalton protein remains in the filament fraction after gel filtration, phosphocellulose chromatography, or salt extraction of microtubule protein. Microtubule protein devoid of 10-nm filaments contains ring structures under depolymerizing conditions, and it polymerizes into microtubules with a characteristically low critical concentration, although all of the 68,000-dalton protein has been removed from it. When cycled microtubule protein is subjected to chromatography on phosphocellulose, the tubulin fraction (PC-tubulin) assembles into microtubules only at concentrations greater than 2 mg/mL. The other fraction, eluted from phosphocellulose at high ionic strength, contains the major 68,000-dalton protein and can be further resolved into two components by centrifugation. The supernatant, which consists mainly of high molecular weight microtubule-associated proteins, stimulates low concentrations of PC-tubulin to assemble. The pellet contains all of the 68,000-dalton protein, consists of 10-nm filaments, and does not stimulate assembly of PC-tublin. Boiling of purified filaments, however, releases several proteins, including the 68,000-dalton protein, and these released proteins stimulate the assembly of PC-tubulin. The morphology and protein composition of the filaments isolated from microtubule preparations by these techniques are very similar to those of mammalian neurofilaments. These results suggest that the major 68,000-dalton protein in cycled microtubule preparations, which may correspond to tubulin assembly protein [Lockwood, A.H. (1978) Cell 13, 613--627], is a constituent of neurofilaments.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D008870	Microtubules	Slender, cylindrical filaments found in the cytoskeleton of plant and animal cells. They are composed of the protein TUBULIN and are influenced by TUBULIN MODULATORS.	Microtubule
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009419	Nerve Tissue Proteins		Proteins, Nerve Tissue,Tissue Proteins, Nerve
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D001923	Brain Chemistry	Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.	Chemistry, Brain,Brain Chemistries,Chemistries, Brain
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014404	Tubulin	A microtubule subunit protein found in large quantities in mammalian brain. It has also been isolated from SPERM FLAGELLUM; CILIA; and other sources. Structurally, the protein is a dimer with a molecular weight of approximately 120,000 and a sedimentation coefficient of 5.8S. It binds to COLCHICINE; VINCRISTINE; and VINBLASTINE.	alpha-Tubulin,beta-Tubulin,delta-Tubulin,epsilon-Tubulin,gamma-Tubulin,alpha Tubulin,beta Tubulin,delta Tubulin,epsilon Tubulin,gamma Tubulin
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular