Microtubule

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154p nutifooddau 18-01-2019 79 10   Download

The C-terminus of thea-chain of tubulin is subject to reversible incorporationof tyrosineby tubulin tyrosine ligase and removal by tubulin carboxypeptidase. Thus, microtu-bules rich in either tyrosinated or detyrosinated tubulin can coexist in the cell. Substitution of the terminal tyrosine by 3-nitrotyrosine has been claimed to cause microtubule dys-function and consequent injury of epithelial lung carcinoma A549 cells. Nitrotyrosine is formed in cells by nitration of tyrosine by nitric oxide-derived species....

9p tumor12 22-04-2013 31 2   Download

Embryos and larvae of the brine shrimp,Artemia francis-cana, were shown previously to possess a protein, now termed p49, which cross-links microtubules in vitro. Molecular characteristics of p49 were described, but the protein’s identity and its role in the cell were not determined. Degenerate oligonucleotide primers designed on the basis of peptide sequence obtained by Edman degradation during this studywereusedtogeneratep49cDNAsbyRT-PCRand thesewere clonedand sequenced.

11p fptmusic 12-04-2013 51 2   Download

The association of tubulin carboxypeptidase with micro-tubules may be involved in the determination of the tyrosi-nation state of the microtubules, i.e. their proportion of tyrosinated vs. nontyrosinated tubulin. We investigated the role of protein phosphatases in the association of carb-oxypeptidase with microtubules in COS cells. Okadaic acid and other PP1/PP2A inhibitors, when added to culture medium before isolation of the cytoskeletal fraction, pro-duced near depletion of the carboxypeptidase activity asso-ciated with microtubules. ...

9p fptmusic 12-04-2013 52 3   Download

Our laboratory is interested in the biochemical and biophysical basis of cell structure. The structure of a cell is determined primarily by its cytoskeleton, which serves as a scaffold to sup-port the plasma membrane, and as a network of tracks along which motor proteins transport sub cellular structures. Our research is therefore focused on the mechanics of the cytoskele-ton, with a particular emphasis on microtubules and microtu-bule-based motors.

17p fptmusic 11-04-2013 52 3   Download

We reported previously on the purification and partial characterization of a putative microtubule-associated protein (MAP) from bovine adrenal cor-tex with an approximate molecular mass of 250 kDa. The protein was expressed ubiquitously in mammalian tissues, and bound to microtubules in vitro and in vivo, but failed to promote tubulin polymerization into microtubules. In the present study, partial amino acid sequencing revealed that the protein shares an identical primary structure with the widely distri-buted iron storage protein, ferritin....

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In living organisms, Ca 2+ signalling is central to cell physi-ology. The Ca 2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N¢,N¢-tetraaceticacid (BAPTA) hasbeenwidelyusedas a probe to test the role of calcium in a large variety of cell functions. Here we show that inmost cell types BAPTAhas a potent actin and microtubule depolymerizing activity and that this activity is completely independent of Ca 2+ chela-tion. Thus, the depolymerizing effect of BAPTA is sharedby a derivative (D-BAPTA) showing a dramatically reduced calcium chelating activity....

10p awards 05-04-2013 30 4   Download

The third repeat fragment (R3) in the four-repeat micro-tubule-binding domain of the water-soluble tau protein has been considered to play an essential role in the protein’s filamentous assembly. To clarify the associational and con-formational features that differentiate R3 from the second repeat, R2, the heparin-induced assembly profiles of these peptide fragments were monitored by the thioflavin fluor-escence method and electron microscopy.

8p dell39 03-04-2013 43 3   Download

Sanguinarine has been shown to inhibit proliferation of several types of human cancer cell including multidrug-resistant cells, whereas it has min-imal cytotoxicity against normal cells such as neutrophils and keratino-cytes. By analyzing the antiproliferative activity of sanguinarine in relation to its effects on mitosis and microtubule assembly, we found that it inhibits cancer cell proliferation by a novel mechanism.

12p inspiron33 26-03-2013 41 3   Download

RasGRF is a family of guanine nucleotide exchange factors with dual spe-cificity for both Ras and Rac GTPases. In this study, using mouse brain extracts, we show that both RasGRF1 and RasGRF2 interact with micro-tubules in an in vitro microtubule assembly system and this binding is very tight. To characterize this association, recombinant purified proteins con-taining different regions of RasGRF1 were tested for their ability to bind microtubules preassembled from pure tubulin.

12p inspiron33 26-03-2013 47 4   Download

We found that benomyl, a benzimidazole fungicide, strongly suppressed the reassembly of cold-depolymerized spindle microtubules in HeLa cells. Benomyl perturbed microtubule-kinetochore attachment and chromosome alignment at the metaphase plate. Benomyl also significantly decreased the distance between the sister kinetochore pairs in metaphase cells and increased the level of the checkpoint protein BubR1 at the kinetochore region, indicating that benomyl caused loss of tension across the kineto-chores....

15p inspiron33 25-03-2013 37 3   Download

Both microtubule destabilizer and stabilizer agents are important molecules in anticancer therapy. In particular, paclitaxel has been demonstrated to be effective for the treatment of ovarian, breast, and nonsmall cell lung carci-nomas. It has been shown that emergence of resistance against this agent correlates with an increase in the relative abundance of tubulin isoform bIII and that the more recently discovered IDN5390 can be effectively used once resistance has emerged.

10p inspiron33 25-03-2013 44 4   Download

Much work has focused on the electrophysiological properties of transient receptor potential channels. Recently, a novel aspect of importance emerged: the interplay of transient receptor potential channels with the cytoskeleton. Recent data suggest a direct interaction and functional reper-cussion for both binding partners.

16p inspiron33 23-03-2013 47 5   Download

TRPP2, also called polycystin-2, the gene product ofPKD2, is a membrane protein defective in 10–15% of cases of autosomal dominant polycystic kidney disease. Mutations in PKD2 are also associated with extrarenal dis-orders, such as hepatic cystogenesis and cardiovascular abnormalities.

9p inspiron33 23-03-2013 35 4   Download

Heterotrimeric G proteins participate in signal transduction by transferring signals from cell surface receptors to intracellular effector molecules. G proteins also interact with microtubules and participate in microtubule-dependent centrosome⁄chromosome movement during cell division, as well as neuronal differentiation.

10p inspiron33 23-03-2013 36 5   Download

The ATP-hydrolysing enzymes (Na + ,K + )-, H + - and Ca 2+ -ATPase are integral membrane proteins that play important roles in the exchange of ions and nutrients between the exterior and interior of cells, and are involved in signal transduction pathways. Activity of these ATPases is reg-ulated by several specific effectors.

11p inspiron33 23-03-2013 39 4   Download

Neurons are highly polarized cells composed of two structurally and func-tionally distinct parts, the axon and the dendrite. The establishment of this asymmetric structure is a tightly regulated process. In fact, alterations in the proteins involved in the configuration of the microtubule lattice are fre-quent in neuro-oncologic diseases.

14p inspiron33 23-03-2013 38 4   Download

Curcumin, a component of turmeric, has potent antitumor activity against several tumor types. However, its molecular target and mechanism of anti-proliferative activity are not clear. Here, we identified curcumin as a novel antimicrotubule agent. We have examined the effects of curcumin on cellu-lar microtubules and on reconstituted microtubules in vitro.

13p inspiron33 23-03-2013 52 4   Download

Vinblastine and paclitaxel (Taxol) are widely used chemotherapeutic drugs that inhibit the normal function of microtubules causing mitotic arrest and cell death. Despite these similarities, the signaling pathways that mediate and regulate cell death induced by these agents remain incompletely under-stood.

11p media19 06-03-2013 48 2   Download

Insulin stimulates glucose uptake by inducing translocation of glucose transporter 4 (GLUT4) from intracellular resides to the plasma membrane. How GLUT4 storage vesicles are translocated from the cellular interior to the plasma membrane remains to be elucidated.

8p media19 05-03-2013 33 2   Download