Kathy A. Suprenant

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A new method for microtubule purification from unfertilized sea-urchin eggs was developed in order to obtain large quantities of calcium- and cold-labile microtubules that contained microtubule-associated components important for mitosis. By taking into consideration the pH, ionic composition of egg cytoplasm, and the physiological temperature for growth of(More)
Vaults are large ribonucleoprotein particles that have been identified in a wide range of eukaryotic organisms. Although present in thousands of copies per cell, their function remains unknown. In this report, we identify the major vault protein in sea urchins as a 107-kDa polypeptide that copurifies with microtubules and ribosomes. Although initially(More)
Microtubules were purified from unfertilized eggs of the sea urchins Arbacia punctulata, Lytechinus pictus, Lytechinus variegatus, and Strongylocentrotus purpuratus. Numerous densely stained particles (24 x 26 nm) are associated with microtubules isolated from each of these sea urchins. The most striking aspect of this structure is an extended, slightly(More)
The piwi/argonaute family of proteins is involved in key developmental processes such as stem cell maintenance and axis specification through molecular mechanisms that may involve RNA silencing. Here we report on the cloning and characterization of the sea urchin piwi/argonaute family member seawi. Seawi is a major component of microtubule-ribonucleoprotein(More)
Microtubule dynamics are influenced by interactions of microtubules with cellular factors and by changes in the primary sequence of the tubulin molecule. Mutations of yeast beta-tubulin C354, which is located near the binding site of some antimitotic compounds, reduce microtubule dynamicity greater than 90% in vivo and in vitro. The resulting intrinsically(More)
Most higher eukaryotic tubulins are separated into alpha- and beta-tubulin when electrophoresed in NaDodSO4- denaturing gels, while many lower eukaryotic tubulins are poorly resolved under these conditions, which include a stacking gel (pH 6.80) and a separating gel (pH 8.80). By lowering the pH of the separating gel to 8.25, we have found that tubulin(More)
A subset of mRNAs, polyribosomes, and poly(A)-binding proteins copurify with microtubules from sea urchin embryos. Several lines of evidence indicate that the interaction of microtubules with ribosomes is specific: a distinct stalk-like structure appears to mediate their association; ribosomes bind to microtubules with a constant stoichiometry through(More)
Vaults are large (13 Mda) ribonucleoprotein particles that are especially abundant in multidrug resistant cancer cells and have been implicated in nucleocytoplasmic drug transport. To understand how these large barrel-shaped complexes are transported through the cytosol, we examined the association of vaults with microtubules both in vitro and in vivo.(More)
Wild-type Saccharomyces cerevisiae tubulin does not bind the anti-mitotic microtubule stabilizing agent paclitaxel. Previously, we introduced mutations into the S. cerevisiae gene for beta-tubulin that imparted paclitaxel binding to the protein, but the mutant strain was not sensitive to paclitaxel and other microtubule-stabilizing agents, due to the(More)