Little is known about the electrostatic/dynamic properties of microtubules, which are considered to underlie their electrostatic interactions with various proteins such as motor proteins, microtubule-associated proteins, and microtubules themselves (lateral association of microtubules). To measure the dielectric properties of microtubules, we developed an experiment system in which the electroo...

Microtubules are filamentous polar polymers with plus and minus ends. This polarity plays a crucial role in a variety of cellular functions such as chromosome movement and organelle transport. To examine the relationship between the growth polarity of microtubules and guanine nucleotide dependence, we polymerized microtubules from axonemes of sea urchin sperm flagella either with GTP or with GT...

Kinetochore microtubules are known to be differentially stable to a variety of microtubuie depolymerization agents compared to the non-kinetochore polar microtubules, but the dynamics of microtubuie attachment to the kinetochore is currently controversial. We have examined the stability of kinetochore microtubules in metaphase PtKx spindles at 23 °C when microtubuie assembly is abruptly blocked...

We have probed the relationship between tubulin posttranslational modification and microtubule stability, using a variation of the antibody-blocking technique. In human retinoblastoma cells we find that acetylated and detyrosinated microtubules represent congruent subsets of the cells' total microtubules. We also find that stable microtubules defined as those that had not undergone polymerizati...

Proper positioning of the cleavage furrow is essential for successful cell division. The mitotic spindle, which consists of dynamic astral microtubules and stable equatorial microtubules is responsible for this process. However, little is known about how microtubules are regulated in a time- and region-dependent manner. Here, we show that α-actinin-regulated cortical actin filament integrity is...

Microtubules with incomplete cylindrical structure are present in isolated mitotic spindles of the sea urchin, Arbacia punctulata. In cross-section they appear C-shaped, and are thus similar to the ' C-microtubules' or 'C-filaments' observed previously in other systems. The C-microtubules are not uniformly distributed within isolated spindles, but are typically numerous in the interzonal region...

The nematode Caenorhabditis elegans should be an excellent model system in which to study the role of microtubules in mitosis, embryogenesis, morphogenesis, and nerve function. It may be studied by the use of biochemical, genetic, molecular biological, and cell biological approaches. We have purified microtubules and microtubule-associated proteins (MAPs) from C. elegans by the use of the anti-...

and 0°C. In both cases the process was reversible (1), 1 the microtubules reappearing when the cold treatment was discontinued. This work deals with the cytoplasmic microtubules in mammalian blood platelets. Unlike the microtubules of the axial filament complex of cilia and flagella, these microtubules are properly preserved only by glutaraldehyde fixation. In platelets the microtubules are arr...

Kinesin-5 is a slow homotetrameric motor protein best known for its essential role in the mitotic spindle, where it limits the rate at which faster motors can move microtubules. In neurons, experimental suppression of kinesin-5 causes the axon to grow faster by increasing the mobility of microtubules in the axonal shaft and the invasion of microtubules into the growth cone. Does kinesin-5 act d...