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1.
Identification of the 190 kD microtubule-associated protein in cultured fibroblasts and its association with interphase and mitotic microtubules 总被引:2,自引:0,他引:2
We previously investigated the biochemical characteristics of microtubule-associated proteins (MAPs) of the adrenal medulla and adrenal cortex and found that they contain a new kind of MAP with a molecular weight of 190,000 (190 kD MAP) as a major species (Kotani, S., H. Murofushi, S. Maekawa, C. Sato, and H. Sakai. Eur. J. Biochem. 156, 23-29, 1986). We now have used an affinity purified anti-(190 kD MAP) antibody and show by indirect immunofluorescent microscopy the association of this MAP with microtubules in situ in TIG-3 cells (human embryonic lung fibroblasts). The 190 kD MAP was present along the interphase and mitotic microtubules, and there was no marked difference between the staining pattern with anti-tubulin and that with anti-(190 kD MAP) antibodies, evidence that the localization of 190 kD MAP is not restricted to the subset of microtubules. We also isolated MAPs from TIG-3 cells and identified their 190 kD MAP as a major heat-stable component. Several other unidentified polypeptides were recovered in the MAP fraction specifically. 相似文献
2.
3.
H Hibasami T Tsukada S Maekawa M Sakurai K Nakashima 《Biochemical and biophysical research communications》1987,144(2):757-762
Ornithine decarboxylase (ODC) was induced in the liver, lung and brain of the mouse injected intraperitoneally with 12-O-tetradecanoylphorbol 13-acetate (TPA), showing maximal enzyme activity four hours after the injection. The increase of ODC activity was due to the enhanced syntheses of mRNA and protein. The induction of ODC activity by TPA was specifically blocked by methylglyoxal bis(butylamidinohydrazone) (MGBB), a competitive inhibitor of ODC and S-adenosylmethionine decarboxylase, but not by the analog methylglyoxal bis(guanylhydrazone) (MGBG). 相似文献
4.
Putrescine, spermidine and spermine were transported into the rat lens against a concentration gradient. This process appeared to be energy-dependent and involved a carrier system different from those for amino acids. Competition experiments suggested that the three polyamines were transported by the same system or very similar systems. Incorporated spermine was converted to spermidine and putrescine, and spermidine was converted to putrescine. In contrast, the conversion of putrescine to spermidine and spermine, or the conversion of spermidine to spermine was not observed. Furthermore, ornithine was not utilized for the synthesis of putrescine. These metabolic characteristics of the polyamines in the rat lens were correlated with the extremely low activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase. Other enzymes of polyamine metabolisms, however, were relatively active. In conclusion, the lens has a very low ability for the de novo synthesis of polyamines. The polyamines in the lens are considered to be supplied form the surrounding intraocular fluid by an active transport system specific for polyamines. 相似文献
5.
Shinichi Ikemoto Seiji Wada Masato Kamizuru Nobuyuki Hayahara Taketoshi Kishimoto Masanobu Maekawa 《Cancer immunology, immunotherapy : CII》1992,34(5):289-293
Summary The authors examined interleukin-2 (IL-2) production and interferon (IFN) production of peripheral blood mononuclear cells in 28 patients with renal cell carcinoma and 17 control subjects. The peripheral blood was obtained prior to the initiation of therapeutic procedures. The patients were divided into two groups according to tumor size, 5 cm and >5 cm. The production of IL-2 and IFN was measured by immunoradiometric assay. As a result, in the patients with tumors >5 cm, IL-2 and IFN production was impaired. However, in the patients with tumors 5 cm, IFN production was enhanced, though IL-2 production was not significantly different from that of the control subjects. There was no significant correlation between IL-2 production and IFN production. 相似文献
6.
A mitosis-specific centrosomal component was studied with a human autoantibody, SP-H, which immunostained mitotic poles and interphase nuclei, and a single polypeptide with an apparent molecular mass of 200 to 230 kDa in various lines of cultured cells. Early mitotic PtK1 cells treated with 10 micrograms/ml taxol contained short bundles of parallel microtubules around the nuclei and cell periphery. At the time of nuclear envelope breakdown, the nuclear staining by SP-H disappeared, and the antigen relocated at one end of the parallel microtubules. Determination of the microtubule polarity demonstrated that the peripheral bundles of microtubules were arranged with their minus ends directed to the cell periphery, and the SP-H antigen was specifically localized at this end. Parallel microtubules were further rearranged first into a fan-like shape, and then into completely radial structures as observed by De Brabander et al. (Int. Rev. Cytol. 101, 215-274 (1986)). The SP-H antigen was always detected at the minus end domain of such microtubule-containing structures during the transformation process. When microtubules were depolymerized by nocodazole treatment, the SP-H antigen appeared as discrete cytoplasmic foci, suggesting that the antigen may self-associate, forming multimeric structures. The antigen in mitotic HeLa cell extracts co-sedimented in vitro with exogenous brain microtubules. The microtubule-associated SP-H antigen was insensitive to ATP extraction, but was removed from microtubules by treatment with 0.5 M NaCl. Thus the 200 to 230 kDa centrosomal component could be a novel microtubule-associated protein with affinity for the minus end of microtubules, and it might play an essential role in the organization of spindle poles during mitosis. 相似文献
7.
Spermidine synthase from rat ventral prostate was inhibited by 2-mercaptoethylamine (MEA). Inhibition of spermidine synthase by MEA was competitive with respect to one of the substrates putrescine, but not competitive with respect to the other substrate decarboxylated S-adenosylmethionine. MEA markedly depressed spermidine and spermine contents in human erythroid leukemia K562 cells, suggesting that these changes resulted from the inhibitory effect of MEA on spermidine synthase in situ. 相似文献
8.
In lactate dehydrogenase (LDH) A subunit deficiency, is there not only a lack of activity but also a lack of subunit production? We demonstrated three remarkable points to answer this question: There are no proteins that immunologically react with anti-A subunits. There are no heterotetramers that react with anti-B subunits. B subunits seem to be genetically produced at normal level, and all of them form only one isoenzyme, LDH-B4. From these points, we concluded that there is a complete lack of A subunit production or production of incomplete A subunits that can neither react with anti-A subunits nor form heterotetramers. 相似文献
9.
An actin-depolymerizing protein (destrin) from porcine kidney. Its action on F-actin containing or lacking tropomyosin 总被引:17,自引:0,他引:17
An Mr 19 000 protein (destrin) that has the ability to rapidly depolymerize F-actin in a stoichiometric manner was purified from porcine kidney by sequential chromatography on DNase I-agarose, hydroxyapatite, and Sephadex G-75. Its actin-depolymerizing activity is reversibly controlled by changes in KCl concentration but is insensitive to Ca2+ concentration. The rate of depolymerization of F-actin by destrin is much faster than that of spontaneous depolymerization induced by dilution and is not markedly decreased by the addition of end-blocking reagents such as cytochalasin B. These results suggest that destrin depolymerizes F-actin by interacting directly with F-actin protomers. Binding of muscle tropomyosin to F-actin slows down the rate of destrin-induced depolymerization of F-actin by about 30-fold. The data suggest that the destrin-induced depolymerization occurs from the ends of F-actin when F-actin is complexed with tropomyosin, but it takes place from the entire length of F-actin in the absence of tropomyosin. 相似文献
10.
Purification and characterization of a Ca2+-dependent actin filament severing protein from bovine adrenal medulla 总被引:3,自引:0,他引:3
S Maekawa M Toriyama S Hisanaga N Yonezawa S Endo N Hirokawa H Sakai 《The Journal of biological chemistry》1989,264(13):7458-7465
We describe the purification of an actin regulatory protein from bovine adrenal medulla. This protein caused a dose-dependent decrease of the specific viscosity of actin solution within 30 s of its addition in a Ca2+-sensitive way. Sedimentation assays and the observation by electron microscopy showed that this effect was ascribable to the fragmentation of actin filaments. This protein apparently promoted nucleation of actin polymerization and increased the critical concentration of actin for polymerization nearly 5-fold, suggesting its binding to the barbed end of actin filaments. The inhibitory effect of this protein on the elongation of actin from the barbed end of the myosin subfragment S1-labeled actin seeds confirmed this suggestion. These properties are similar to those of gelsolin. However, the physicochemical properties of this protein having a single polypeptide chain with a molecular weight of 74,000, a Stokes radius of 3.9 nm, a sedimentation coefficient (s0(20),w) of 4.5 S, and an immunological characterization showed that this protein is different from gelsolin. 相似文献