Biomaterial Database

Characterization of the microtubule-activated ATPase of brain cytoplasmic dynein (MAP 1C). 1988

H S Shpetner, and B M Paschal, and R B Vallee

Cell Biology Group, Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545.

We recently found that the brain cytosolic microtubule-associated protein 1C (MAP 1C) is a microtubule-activated ATPase, capable of translocating microtubules in vitro in the direction corresponding to retrograde transport. (Paschal, B. M., H. S. Shpetner, and R. B. Vallee. 1987b. J. Cell Biol. 105:1273-1282; Paschal, B. M., and R. B. Vallee. 1987. Nature [Lond.]. 330:181-183.). Biochemical analysis of this protein (op. cit.) as well as scanning transmission electron microscopy revealed that MAP 1C is a brain cytoplasmic form of the ciliary and flagellar ATPase dynein (Vallee, R. B., J. S. Wall, B. M. Paschal, and H. S. Shpetner. 1988. Nature [Lond.]. 332:561-563). We have now characterized the ATPase activity of the brain enzyme in detail. We found that microtubule activation required polymeric tubulin and saturated with increasing tubulin concentration. The maximum activity at saturating tubulin (Vmax) varied from 186 to 239 nmol/min per mg. At low ionic strength, the Km for microtubules was 0.16 mg/ml tubulin, substantially lower than that previously reported for axonemal dynein. The microtubule-stimulated activity was extremely sensitive to changes in ionic strength and sulfhydryl oxidation state, both of which primarily affected the microtubule concentrations required for half-maximal activation. In a number of respects the brain dynein was enzymatically similar to both axonemal and egg dyneins. Thus, the ATPase required divalent cations, calcium stimulating activity less effectively than magnesium. The MgATPase was inhibited by metavandate (Ki = 5-10 microM for the microtubule-stimulated activity), 1 mM NEM, and 1 mM EHNA. In contrast to other dyneins, the brain enzyme hydrolyzed CTP, TTP, and GTP at higher rates than ATP. Thus, the enzymological properties of the brain cytoplasmic dynein are clearly related to those of other dyneins, though the brain enzyme is unique in its substrate specificity and in its high sensitivity to stimulation by microtubules.

UI	MeSH Term	Description	Entries
D008869	Microtubule-Associated Proteins	High molecular weight proteins found in the MICROTUBULES of the cytoskeletal system. Under certain conditions they are required for TUBULIN assembly into the microtubules and stabilize the assembled microtubules.	Ensconsin,Epithelial MAP, 115 kDa,Epithelial Microtubule-Associate Protein, 115 kDa,MAP4,Microtubule Associated Protein,Microtubule Associated Protein 4,Microtubule Associated Protein 7,Microtubule-Associated Protein,Microtubule-Associated Protein 7,E-MAP-115,MAP1 Microtubule-Associated Protein,MAP2 Microtubule-Associated Protein,MAP3 Microtubule-Associated Protein,Microtubule Associated Proteins,Microtubule-Associated Protein 1,Microtubule-Associated Protein 2,Microtubule-Associated Protein 3,7, Microtubule-Associated Protein,Associated Protein, Microtubule,E MAP 115,Epithelial Microtubule Associate Protein, 115 kDa,MAP1 Microtubule Associated Protein,MAP2 Microtubule Associated Protein,MAP3 Microtubule Associated Protein,Microtubule Associated Protein 1,Microtubule Associated Protein 2,Microtubule Associated Protein 3,Microtubule-Associated Protein, MAP1,Microtubule-Associated Protein, MAP2,Microtubule-Associated Protein, MAP3,Protein 7, Microtubule-Associated,Protein, Microtubule Associated,Protein, Microtubule-Associated
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
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
D011189	Potassium Chloride	A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.	Slow-K,Chloride, Potassium
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D003600	Cytosol	Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.	Cytosols
D004398	Dyneins	A family of multi-subunit cytoskeletal motor proteins that use the energy of ATP hydrolysis, generated by a ring of AAA ATPASES in the dynein heavy chain, to power a variety of cellular functions. Dyneins fall into two major classes based upon structural and functional criteria.	ATPase, Dynein,Adenosinetriphosphatase, Dynein,Dynein,Dynein ATPase,Dynein Adenosinetriphosphatase,Dynein Heavy Chain,Dynein Intermediate Chain,Dynein Light Chain,Dynein Light Intermediate Chain,Adenosine Triphosphatase, Dynein,Dynein Heavy Chains,Dynein Intermediate Chains,Dynein Light Chains,Dynein Light Intermediate Chains,Chain, Dynein Heavy,Chain, Dynein Intermediate,Chain, Dynein Light,Chains, Dynein Heavy,Chains, Dynein Intermediate,Chains, Dynein Light,Dynein Adenosine Triphosphatase,Heavy Chain, Dynein,Heavy Chains, Dynein,Intermediate Chain, Dynein,Intermediate Chains, Dynein,Light Chain, Dynein,Light Chains, Dynein
D000251	Adenosine Triphosphatases	A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.	ATPases,Adenosinetriphosphatase,ATPase,ATPase, DNA-Dependent,Adenosine Triphosphatase,DNA-Dependent ATPase,DNA-Dependent Adenosinetriphosphatases,ATPase, DNA Dependent,Adenosinetriphosphatases, DNA-Dependent,DNA Dependent ATPase,DNA Dependent Adenosinetriphosphatases,Triphosphatase, Adenosine
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