Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.6.4.4 (kinesin)
5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bovine brain kinesin separates into two components on sucrose density gradient centrifugation. The predominant component is a heterotetramer of two 120 kDa alpha subunits and two 64 kDa beta subunits with an sedimentation coefficient of 9.6 S and a low Vm rate of microtubule-stimulated ATPase of 1.3 +/- 0.5 sec-1 at 25 degrees, pH 7.0. The minor element is a homodimer of two alpha subunits without beta subunits with a sedimentation coefficient of 6.9 S and a higher Vm rate of microtubule-stimulated ATPase of 7.0 +/- 1.9 sec-1. Microtubules stimulate the rate of release of ADP from the active site of the tetramer, but the rate of release is not fast enough to account for the rate of steady state ATP hydrolysis. Further complexity is indicated by biphasic release kinetics. In spite of the large difference in Vm ATPase rate for the two species, both drive the sliding of sea urchin axonemes over glass surfaces at the same velocity.
...
PMID:Characterization of alpha 2 beta 2 and alpha 2 forms of kinesin. 182 68

Kinesin is a mechanochemical ATPase that induces translocation of latex beads along microtubules and microtubule gliding on a glass surface. This protein is thought to be a motor for the movement of membranous organelles in cells. Recently Hollenbeck and Swanson [Hollenbeck, P. J. & Swanson, J. A. (1990) Nature (London) 346, 864-866] showed that kinesin is involved in the positioning of tubular lysosomes in macrophages. However, the role of this protein in the movement of organelles was not yet clear. We used a polyclonal antibody against the kinesin heavy chain that inhibited kinesin-dependent microtubule gliding in vitro to study the role of kinesin in the movement of pigment granules in melanophores of the teleost black tetra (Gymnocorymbus ternetzi). Microinjection of the antibody into cultured melanophores did not produce any specific effect on the aggregation of pigment granules in melanophores, but it did result in a strong dose-dependent inhibition of the dispersion. Immunoblotting of melanophore extracts showed that the kinesin antibody reacted in these cells with a single protein component with a molecular mass of 135 kDa. Thus, kinesin is responsible for the movement of pigment granules from the center to the periphery of the melanophore.
...
PMID:Kinesin is responsible for centrifugal movement of pigment granules in melanophores. 182 87

We examined the ability of kinesin to support the movement of adrenal medullary chromaffin granules on microtubules in a defined in vitro system. We found that kinesin and ATP are all that is required to support efficient (33% vesicle motility) and rapid (0.4-0.6 micron/s) translocation of secretory granule membranes on microtubules in the presence of a low-salt motility buffer. Kinesin also induced the formation of microtubule asters in this buffer, with the plus ends of microtubules located at the center of each aster. This observation indicates that kinesin is capable of promoting active sliding between microtubules toward their respective plus ends, a movement analogous to that of anaphase b in the mitotic spindle. The fact that vesicle translocation, microtubule sliding, and microtubule-dependent kinesin ATPase activities are all enhanced in low-salt buffer establishes a functional parallel between this translocator and other motility ATPases, myosin, and dynein.
...
PMID:Purified kinesin promotes vesicle motility and induces active sliding between microtubules in vitro. 183 Jun 66

The 'motor' proteins of eukaryotic cells contain specialized domains that hydrolyse ATP to produce force and movement along a cytoskeletal polymer (actin in the case of the myosin family; microtubules in the case of the kinesin family and dyneins). There are motor-protein superfamilies in which each member has a conserved force-generating domain joined to a different 'tail' which conveys specific attachment properties. The minus-end-directed microtubule motors, the dyneins, may also constitute a superfamily of force-generating proteins with distinct attachment domains. Axonemal outer-arm dynein from sea urchin spermatozoa is a multimeric protein consisting of two heavy chains (alpha and beta) with ATPase activity, three intermediate chains and several light chains. Here I report the sequence of cloned complementary DNA encoding the beta heavy chain of a dynein motor molecule. The predicted amino-acid sequence reveals four ATP-binding consensus sequences in the central domain. The dynein beta heavy chain is thought to associate transiently with a microtubule during ATP hydrolysis, but the ATP-dependent microtubule-binding sequence common to the kinesin superfamily is not found in the dynein beta heavy chain. These unique features distinguish the dynein beta heavy chain from other motor protein superfamilies and may be characteristic of the dynein superfamily.
...
PMID:Four ATP-binding sites in the midregion of the beta heavy chain of dynein. 183 Sep 24

Mutations in the unc-104 gene of the nematode C. elegans result in uncoordinated and slow movement. Transposon insertions in three unc-104 alleles (e2184, rh1016, and rh1017) were used as physical markers to clone the unc-104 gene. DNA sequence analysis of unc-104 cDNAs revealed an open reading frame capable of encoding a 1584 amino acid protein with similarities to kinesin heavy chain. The similarities are greatest in the amino-terminal ATPase and microtubule-binding domains. Although the primary sequence relatedness to kinesin is weak in the remainder of the molecule, the predicted secondary structure and regional isoelectric points are similar to kinesin heavy chain.
...
PMID:The C. elegans unc-104 gene encodes a putative kinesin heavy chain-like protein. 184 75

The protocols described here have proved to be an effective method for preparation of kinesin suitable for biochemical, biophysical, and immunological analyses. Beginning with a 1.2-liter cytosolic extract of bovine brain containing approximately 24 g of protein, 2 mg of approximately 95% pure kinesin can be obtained within 2 days. There are four major enrichment steps, as summarized in Fig. 6 and Table I. Based on quantitative SDS-PAGE, we estimate that these steps result in a purification of more than 300-fold. The ATPase activity in the presence of microtubules is substantial, and the kinetic properties are consistent with cellular levels of ATP (Km approximately 0.2 mM) and microtubules (apparent Km for activation approximately 1.9 microM) in the axon. Minor modifications should allow the procedure to be enlarged or reduced in scale, or adapted to the brains of other vertebrate species. The availability of such procedures will greatly facilitate future studies of the cell and molecular biology of kinesin.
...
PMID:Purification of kinesin from bovine brain and assay of microtubule-stimulated ATPase activity. 185 39

Movement of membrane-bounded organelles to intracellular destinations requires properly oriented microtubules and force-generating enzymes, such as the microtubule-stimulated ATPase kinesin. Kinesin is a heterotetramer with two heavy chain (approximately 124-kDa) and two light chain (approximately 64-kDa) subunits. Kinesin heavy chains contain both ATP- and microtubule-binding domains and are capable of force generation in vitro. Functions of the light chains are undetermined, although evidence suggests they interact with membrane surfaces. We have used molecular genetic approaches to dissect the kinesin light chain structure. Three distinct kinesin light chain cDNAs were cloned and sequenced from rat brain, and they were found to result from alternative splicing of a single gene. Polypeptides encoded by these cDNAs are identical except for their carboxyl ends. Synthesis of multiple light chains, differing from one another in primary structure, could provide a means of generating multiple, functionally specialized forms of the kinesin holoenzyme.
...
PMID:Molecular genetics of kinesin light chains: generation of isoforms by alternative splicing. 194 31

It has been previously shown that a class of microtubule proteins, the so-called microtubule-associated proteins (MAPs), binds to the C-terminal part of tubulin subunits. We show here that microtubules composed of tubulin whose 4-kDa C-terminal domain was cleaved by subtilisin (S-microtubules) are unable to bind MAPs but can still bind the anterograde translocator protein kinesin and the retrograde translocator dynein. Binding of both motors to S-microtubules, like their binding to normal microtubules, was ATP-dependent. In addition, direct competition experiments showed that binding sites for kiensin and MAPs on the microtubule surface lattice do not overlap. Furthermore, S-microtubules stimulated the ATPase activity of kinesin at least 8-fold, and the affinities of kinesin for control and S-microtubules were identical. S-microtubules were able to glide along kinesin-coated coverslips at a rate of 0.2 microns/s, the same rate as control microtubules. We conclude, that unlike MAPs, kinesin and cytoplasmic dynein bind to the tubulin molecule outside the C-terminal region.
...
PMID:Microtubule-associated proteins and microtubule-based translocators have different binding sites on tubulin molecule. 213 10

The circular dichroic spectra of outer arm dynein from sea urchin sperm flagella, of its separated alpha and beta heavy-chain complexes, and of the two major fragments produced by tryptic digestion of the beta heavy chain have been measured over the range 190-240 nm. Although the spectra show significant individuality, in all cases they qualitatively resemble those of typical globular proteins with mixed regions of alpha-helix and beta-sheet (alpha/beta-type structure) or with separate alpha-helix- and beta-sheet-rich regions (alpha+beta-type structure). Quantitative analyses of the spectra by both constrained and unconstrained least-squares curve-fitting procedures indicate that the intact dynein contains approximately 26% alpha-helix. The separated beta heavy-chain complex and its ATPase-containing amino-terminal domain (fragment A) both have spectra resembling that of intact dynein, and they appear to contain 32% and 23% alpha-helix, respectively. The carboxy-terminal domain of the beta heavy chain (fragment B) and the separated alpha heavy chain have significantly different spectra; however, they each appear to contain 26-36% alpha-helix. These data suggest that dynein does not contain an extensive alpha-helical domain, such as is found in the carboxy-terminal rod region of the other motor proteins myosin and kinesin.
...
PMID:A circular dichroic study of helical structure in flagellar dynein. 214 99

Kinesin is a microtubule-activated ATPase that moves objects toward the plus end of microtubules and makes microtubules glide along a glass surface. Here we investigate a remarkable effect of the nonhydrolyzable analogue of ATP, adenosine 5'-[beta,gamma-imido]triphosphate (p[NH]ppA), on kinesin-driven microtubule gliding. Microtubule gliding that has been blocked by rapid replacement of ATP with p[NH]ppA requires 1-2 min of exposure to ATP before microtubule gliding resumes. This latency is not shortened by prolonged washing of p[NH]ppA-blocked microtubules in nucleotide-free buffer for up to 15 min, suggesting that ATP binding to a second nucleotide binding site on kinesin triggers the release of bound p[NH]ppA. To test this hypothesis, the release of [3H]p[NH]ppA from kinesin-microtubule complexes was followed in parallel biochemical assays. In nucleotide-free buffer, the bound p[NH]ppA was released over several hours from the complexes. However, addition of ATP caused the release of p[NH]ppA from the kinesin-microtubule complexes within 2 min, which was similar to the latent period for start-up of microtubule gliding after p[NH]ppA inhibition. The stoichiometry of p[NH]ppA bound per kinesin heavy chain at saturation was estimated to be approximately 1:2. These results suggest a model in which each molecule of kinesin has at least two nucleotide binding sites that alternately bind nucleotide.
...
PMID:Delayed start-up of kinesin-driven microtubule gliding following inhibition by adenosine 5'-[beta,gamma-imido]triphosphate. 214 8


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---