Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.4.4 (kinesin)
 5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The recombinant product (rK39) of the 39 amino acid repeats encoded by a kinesin-like gene of visceral Leishmania spp. was further evaluated by enzyme-linked immunosorbent assay (ELISA) for its diagnostic potential in Indian kala-azar (VL) and post kala-azar dermal leishmaniasis (PKDL). Anti-rK39 antibodies were highly positive in 20 symptomatic cases, including 6 resistant to single or double chemotherapy, but became negligible or absent in 9 recently cured patients. Endpoint titration of samples from the 20 active cases showed that the anti-rK39 IgG titers fell within a wide range of 10(-2) to > 10(-6), and that their mean was > 1 order of magnitude higher than in VL reported previously. The anti-rK39 IgG titers were correlated with parasite burden found in the patients and remained undiminished in those refractory to chemotherapy. These results indicate that: (1) the K39 epitope is conserved in Indian strains of Leishmania donovani, (2) the extremely high levels of K39 antibodies in both VL and PKDL suggest the application of rK39 for sensitive and specific serodiagnosis, and (3) rK39 ELISA is also valuable for prognostic evaluation of both diseases.
J Parasitol 1995 Dec
PMID:Diagnostic and prognostic value of K39 recombinant antigen in Indian leishmaniasis. 854 37

Plasma membrane disruptions are resealed by an active molecular mechanism thought to be composed, in part, of kinesin, CaM kinase, snap-25, and synaptobrevin. We have used HRP to mark the cytoplasmic site of a mechanically induced plasma membrane disruption. Transmission electron microscopy revealed that vesicles of a variety of sizes rapidly (s) accumulate in large numbers within the cytoplasm surrounding the disruption site and that microvilli-like surface projections overlie this region. Scanning electron microscopy confirmed that tufts of microvilli rapidly appear on wounded cells. Three assays, employing the membrane specific dye FM1-43, provide quantitative evidence that disruption induces Ca(2+)-dependent exocytosis involving one or more of the endosomal/lysosomal compartments. Confocal microscopy revealed the presence in wounded cells of cortical domains that were strikingly depleted of FM dye fluorescence, suggesting that a local bolus of exocytosis is induced by wounding rather than global exocytosis. Finally, flow cytometry recorded a disruption-induced increase in cell forward scatter, suggesting that cell size increases after injury. These results provide the first direct support for the hypothesis that one or more internal membrane compartments accumulate at the disruption site and fuse there with the plasma membrane, resulting in the local addition of membrane to the surface of the mechanically wounded cell.
J Cell Biol 1995 Dec
PMID:Vesicle accumulation and exocytosis at sites of plasma membrane disruption. 855 41

Experiments indicate that depolymerization of microtubules generates sufficient force to produce the minus-end-directed transport of chromosomes during mitosis (Koshland et al., 1988). In vitro, analogous transport of kinesin-coated microspheres exhibits a paradoxical effect. Minus-end-directed transport of the microspheres driven by depolymerization is enhanced by the presence of ATP, which fuels the motor action of kinesin driving the microspheres in the opposite direction, toward the plus end of the microtubule. Here we present a mathematical model to explain this behavior. We postulate that a microsphere at the plus end of the microtubule facilitates depolymerization and hence enhances minus-end-directed transport. The force-velocity curve of the model is derived; it has the peculiar feature that velocity is maximal at some positive load (opposing the motion) rather than at zero load. The model is used to simulate the stochastic process of microsphere-facilitated depolymerization-driven transport. Simulated trajectories at low load show distinctive runs and pauses, the statistics of which are calculated from the model. The statistics of the process provide sufficient information to determine all of the model's parameters.
Biophys J 1995 Dec
PMID:Force production by depolymerizing microtubules: load-velocity curves and run-pause statistics. 859 34

We show that microtubule polymers can be immobilized selectively on lithographically patterned silane surfaces while retaining their native properties. Silane films were chemisorbed on polished silicon wafers or glass coverslips and patterned using a deep UV lithographic process developed at the Naval Research Laboratory. Hydrocarbon and fluorocarbon alkyl silanes, as well as amino and thiol terminal alkyl silanes, were investigated as substrates for microtubule adhesion with retention of biological activity. Microtubules were found to adhere strongly to amine terminal silanes while retaining the ability to act as substrates for the molecular motor protein kinesin. Aminosilane patterns with linewidths varying from 1 to 50 microns were produced lithographically and used to produce patterns of selectively adhered microtubules. Microtubules were partially aligned on the patterned lines by performing the immobilization in a fluid flow field. Patterns were imaged with atomic force microscopy and differential interference contrast microscopy. Motility assays were carried out using kinesin-coated beads and observed with differential interference contrast microscopy. Kinesin bead movement on the patterned microtubules was comparable to movement on microtubule control surfaces.
Biophys J 1995 Dec
PMID:Selective adhesion of functional microtubules to patterned silane surfaces. 859 84

Sertoli cells are polarized epithelial cells of the seminiferous epithelium which provide structural and physiological support for differentiating germ cells. They establish different basal and adluminal environments for the selective nurturing of pre- and post-meiotic germ cells within the seminiferous epithelium, segregated by the Sertoli-Sertoli cell tight junctional complex, the blood-testis barrier. Tight junction formation between epithelial cells in vitro is a critical polarizing event associated with changes in polarized targeting of membrane-specific proteins and reorganization of microtubules, centrioles, and the Golgi apparatus. To investigate whether tight junction formation is associated with organelle reorganization in Sertoli cells in vivo, we have characterized distribution patterns of Sertoli cell microtubules, the mechanoenzymes kinesin and cytoplasmic dynein, and the Golgi apparatus during tight junction formation in developing rat testis. Immunocytochemistry on samples taken at 5, 10, 15, 20, and 25 days of age was used to examine the distribution of these proteins during the extensive cellular reorganization that culminates in the formation of the blood-testis barrier at 19 days of age. Our data show that the distribution patterns reflect the extensive intercellular repositioning of tubule cells in developing seminiferous tubules, but that changes in intracellular organization are not temporally associated with formation of the blood-testis barrier.
Microsc Res Tech 1995 Dec 15
PMID:Distribution of Sertoli cell microtubules, microtubule-dependent motors, and the Golgi apparatus before and after tight junction formation in developing rat testis. 860 98

To obtain an overall three-dimensional picture of the interaction between microtubules and the motor proteins of the kinesin family it will be necessary to take account of both atomic resolution structures obtained by X-ray crystallography and medium resolution reconstructions obtained by electron cryomicroscopy. We examine the problems associated with obtaining the required structural information from electron micrographs of vitreous ice-embedded microtubules decorated with motor domains. We find that the minus-end directed motor, ncd, decorates microtubules with an 80 A periodicity as for kinesin. Our theoretical analysis and experiments with ncd illustrate the difficulty in determining unambiguously the surface lattice organization by diffraction analysis of micrographs. 3D reconstructions of decorated microtubules are required to accurately locate the motor domains. Helical diffraction theory is not usually applicable because microtubules are cylindrical structures that rarely have complete helical symmetry. We propose using a back-projection method based on the long pitch helices formed by individual protofilaments. Model reconstructions show that this approach is feasible.
Proteins 1995 Dec
PMID:Toward understanding the structure and interactions of microtubules and motor proteins. 874 46

Light stimulation of locust photoreceptors causes a translocation of submicrovillar cisternae of the endoplasmic reticulum away from the rhabdome, and a movement of mitochondria towards the rhabdome. To examine whether the microtubule cytoskeleton could be involved in these organelle movements, we have analysed the distribution of the microtubule-dependent motor proteins kinesin and cytoplasmic dynein in the retina of the locust Schistocerca gregaria. Both kinesin and cytoplasmic dynein are associated with vesicular structures that are distinct from mitochondria and the submicrovillar endoplasmic reticulum. These results, together with the previous demonstration of a lack of microtubules in the cell area of light-dependent organelle movements, provide evidence that the microtubule cytoskeleton is not involved with light-induced organelle translocations.
Cell Tissue Res 1996 Dec
PMID:Immunolocalization of kinesin and cytoplasmic dynein in the retina of the locust Schistocerca gregaria. 892 58

To measure force generation and characterize the relationship between force and velocity in kinesin-driven motility we have developed a centrifuge microscope sperm-gliding motility assay. The average (extrapolated) value of maximum isometric force at low kinesin density was 0.90 +/- 0.14 pN. Furthermore, in the experiments at low kinesin density, sperm pulled off before stall at forces between 0.40 and 0.75 pN. To further characterize our kinesin-demembranated sperm assay we estimated maximum isometric force using a laser trap-based assay. At low kinesin density, 4.34 +/- 1.5 pN was the maximum force. Using values of axoneme stiffness available from other studies, we concluded that, in our centrifuge microscope-based assay, a sperm axoneme functions as a lever arm, magnifying the centrifugal force and leading to pull-off before stall. In addition, drag of the distal portion of the axoneme is increased by the centrifugal force (because the axoneme is rotated into closer proximity to the glass surface) and represents an additional force that the kinesin motor must overcome.
Biophys J 1996 Dec
PMID:Kinesin force generation measured using a centrifuge microscope sperm-gliding motility assay. 896 16

ncd is a microtubule motor protein from Drosophila, having a 40 kDa domain homologous to the kinesin motor domain. In the present study, we investigated the circular dichroism (CD) spectra of the ncd motor domain in comparison with those of the kinesin motor domain. Although the two are about 40% identical in amino acid sequence, and recent X-ray crystallographic studies [Sablin, Kull, Cooke, Vale, and Fletterick (1996) Nature 380, 555-559; Kull, Sablin, Lau, Fletterick, and Vale (1996) Nature 380, 550-555] indicate that their core structures are nearly identical, the far UV CD spectra of ncd and kinesin motor domains, both being monomeric, were considerably different from each other, suggesting a significant difference in the secondary, especially loop structures. The motor domain of ncd, like that of kinesin, contains tightly associating ADP even after purification. We removed ADP from the ncd motor domain by gel filtration in the presence of EDTA and high salt. The resultant protein, however, was likely to be in an inactive state, since it bound ATP slowly. The far UV CD spectrum of the ncd motor domain devoid of ADP was nearly identical to that of the ncd motor domain with bound ADP. This indicated that the removal of ADP did not affect the backbone structure in the presence of high salt. On the other hand, the near UV CD spectrum of the ADP-free ncd motor domain differed from that of the ncd motor domain. ADP complex, one possibility being that the local conformation was changed upon removal of bound ADP. The near UV CD spectra of kinesin motor domain also showed a difference between the ADP-bound form and the nucleotide-free form, although the difference was much smaller.
J Biochem 1996 Dec
PMID:Comparison of ncd and kinesin motor domains by circular dichroism spectroscopy. 901 Jul 67

The non-claret disjunctional protein (Ncd) is a kinesin-related microtubule motor that moves toward the negative end of microtubules. The kinetic mechanism of the monomer motor domain, residues 335-700, satisfied a simple scheme for the binding of 2'-3'-O-(N-methylanthraniloyl) (MANT) ATP, the hydrolysis step, and the binding and release of MANT ADP, where T, D, and Pi refer to nucleotide triphosphate, nucleotide diphosphate, and inorganic phosphate, respectively, and MtN is the complex of an Ncd motor domain with a microtubule site. Rate constants k1 and k-4 are the rates of a first order step, an isomerization induced by nucleotide binding. The apparent second order rate constants for the binding steps are 1.5 x 10(6) M-1 s-1 for MANT ATP and 3.5 x 10(6) M-1 s-1 for MANT ADP (conditions, 50 mM NaCl, pH 6.9, 21 degrees C). The rate constant of the hydrolysis step (k2) was obtained from quench flow measurements of the phosphate burst phase corrected for the contribution of the rate of product release to the transient rate constant. The rate of phosphate dissociation was not measured; the value was assigned to account for a steady state rate of 3 s-1. The MtN complex is dissociated by ATP at a rate of 10 s-1 based on light scattering measurements. Dissociation constants of Ncd-nucleotide complexes from microtubules increased in the order adenosine 5'-O-(thiotriphosphate) (ATPgammaS) < ADP-AlF4 < ATP < ADP < ADP-vanadate. Comparison of the properties of Ncd with a monomeric kinesin K332 (Ma and Taylor (1997) J. Biol. Chem. 272, 717-723) showed a close similarity, except that the rate constants for the hydrolysis and ADP release steps and the steady state rate are approximately 15-20 times smaller for Ncd. There are two differences that may affect the reaction pathway. The rate of dissociation of MtN by ATP is comparable to the rate of the hydrolysis step, and N.T may dissociate in the cycle, whereas for kinesin, dissociation occurs after hydrolysis. The rate of dissociation of MtN by ADP is larger than the rate of ADP release from MtN.D, whereas for the microtubule-kinesin complex, the rate of dissociation by ADP is smaller than the rate of ADP release. The monomeric Mt.Ncd complex is not processive.
J Biol Chem 1997 Dec 05
PMID:Kinetic mechanism of monomeric non-claret disjunctional protein (Ncd) ATPase. 938 11


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