Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Use of multiple monoclonal antibodies to characterize the major microtubule-associated protein in sea urchin eggs (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 431-446 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubules assembled from sea urchin eggs with the use of taxol contain a 77,000-dalton protein as the major nontubulin component [Vallee and Bloom (1983): Proc Natl. Acad. Sci. U.S.A. 80:6259-6263]. We have raised five monoclonal antibodies to this protein to aid in its characterization. Immunoblot analysis of the sea urchin microtubule purification fractions indicated that the protein copurified quantitatively with microtubules. All five antibodies stained the mitotic spindle of dividing sea urchin eggs by immunofluorescence microscopy, indicating that the protein was a component of the mitotic spindle and suggesting that it was actually localized on microtubules in vivo. Immunofluorescent staining of higher resolution was observed in a subpopulation of the coelomic cells found in adult sea urchins, confirming that the 77,000-dalton protein is indeed present on microtubules in vivo. Because taxol was not used for the immunofluorescence experiments, we conclude that the microtubule-associated protein (MAP)-like behavior of the 77,000-dalton protein in vitro was not induced artifactually by taxol. To determine whether this protein is a component of sea urchin microtubules in general, cilia obtained from blastula stage embryos and sperm tail flagella were analyzed with the antibodies. The protein was undetectable by both immunoblot analysis and immunofluorescence microscopy in both preparations of axonemal microtubules. These results indicated that the 77,000-dalton MAP is restricted to cytoplasmic and mitotic microtubules in the sea urchin. Furthermore, in view of its particular abundance in embryos, whose microtubules are devoted substantially to mitosis, the 77,000-dalton MAP is likely to play an important role in regulating the activity of mitotic spindle microtubules in the sea urchin.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970050602
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Copurification of kinesin polypeptides with microtubule-stimulated Mg-ATPase activity and kinetic analysis of enzymatic properties (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 12 (1989), S. 195-215 
    Details
    ISSN: 0886-1544
    Keywords: mechanochemistry ; fast axonal transport ; cytoskeleton ; vesicle ; motor protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Determination of kinetic properties for kinesin adenosine triphosphatase (ATPase), a proposed motor for transport of membranous organelles, requires adequate amounts of kinesin with a consistent level of enzymatic activity. A purification procedure is detailed that produces approximately 2 mg of kinesin at up to 96% purity from 800 g of bovine brain. This protocol consists of a microtubule affinity step using 5′-adenylylimidodiphosphate (AMP-PNP); followed by gel filtration, ion exchange, and hydroxylapatite chromatography; and then sucrose density gradient centrifugation. The microtubule-activated ATPase activity of kinesin coeluted with kinesin polypeptides throughout the purification. Highly purified kinesin had a Vmax of 0.31 μmol/min/mg in the presence of microtubules, with a Km for ATP of 0.20 mM. The kinetic constants obtained in these studies compare favorably with physiological levels of ATP and microtubules. Variations in buffer conditions for the assay were found to affect ATPase activity significantly. A study of the ability of kinesin to utilize a variety of cation-ATP complexes indicated that kinesin is a microtubule-stimulated Mg-ATPase, but kinesin is able to hydrolyze Ca-ATP, Mn-ATP, and Co-ATP as well as Mg-ATP in the presence of microtubules. In the absence of microtubules, Ca-ATP appears to be the best substrate. Studies with several inhibitors of ATPases determined that vanadate inhibited kinesin ATPase at the lowest concentrations of inhibitor, but significant inhibition of the ATPase also occurred with submillimolar concentrations of AMP-PNP. Other inhibitors of kinesin include N-ethylmaleimide, adenosine diphosphate (ADP), pyrophosphate, and tripolyphosphate. Further characterization of the kinetic properties of the kinesin ATPase is important for understanding the molecular mechanisms for transport of membranous organelles along microtubules.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970120403
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Glucocorticoid agonists as well as antagonists are effective inducers of mouse mammary tumor virus RNA in mouse mammary tumor cells treated with inhibitors of ADP-ribosylation (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 129 (1986), S. 36-42 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Glucocorticoids increase expression of specific genes by a mechanism involving binding to and “activation” of a specific receptor protein. Other steroids, such as RU 486, bind to the glucocorticoid receptor but the resultant steroidreceptor complex is unable to activate glucocorticoid sensitive genes. In the present study we have observed that steroid regulation of the glucocorticoidregulated mouse mammary tumor virus (MMTV) genome in cultured mouse mammary tumor cells is altered by treatment of the cells with inhibitors of (ADP-ribose)n synthetase. The ability of glucocorticoid agonists to increase MMTV is about 2-fold increased by the inhibitor treatment. Interestingly, RU 486 and other steroids that are normally inactive in control cells are very good inducers of MMTV in the treated cells. This alteration in MMTV expression is associated with a 37% increase in nuclear binding of the glucocorticoid, triamcinolone acetonide, and also RU 486 in the inhibitor-treated cells. Steroids that do not bind to the glucocorticoid receptor are not inducers in control or in treated cells. The results point to a role for ADP-ribosylation of proteins as a negative regulator of MMTV expression and suggest a mechanism for activation of steroid-sensitive genomes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041290106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...