Strains of Aspergillus containing the benA22 mutation are resistant to benomyl for vegetative growth but do not produce conidia. To test whether conidiation involved an additional benomyl-sensitive tubulin (i.e., was mediated by a tubulin other than the tubulins coded for by the benA locus), a collection of mutants was produced that formed conidia in the presence of benomyl, i.e., were conidiat...

The folding of actin and tubulin is mediated via interaction with a heteromeric toroidal complex (cytoplasmic chaperonin) that hydrolyzes ATP as part of the reaction whereby native proteins are ultimately released. Vertebrate actin-related protein (actin-RPV) (also termed centractin) and gamma-tubulin are two proteins that are distantly related to actin and tubulin, respectively: gamma-tubulin ...

The Notch signal pathway plays important roles in proliferation, apoptosis, and differentiation. Abnormalities in Notch signaling are linked to many human diseases. After ligand binding, Notch signaling is activated through the cleavage of Notch receptors to release and translocate the Notch intracellular domain into the nucleus. The Notch1 receptor intracellular domain (N1IC), the activated fo...

The growing and shortening dynamics of individual bovine brain microtubules at their plus ends at steady state in vitro, assembled from isotypically pure alpha beta II, alpha beta III, or alpha beta IV tubulin dimers, were determined by differential interference contrast video microscopy. Microtubules assembled from the purified alpha beta III isotype were considerably more dynamic than microtu...

BACKGROUND Mammalian megakaryocytes release blood platelets through a remarkable process of cytoplasmic fragmentation and de novo assembly of a marginal microtubule band. Cell-specific components of this process include the divergent beta-tubulin isoform beta1 that is expressed exclusively, and is the predominant isoform, in platelets and megakaryocytes. The functional significance of this rest...

Microtubule-associated proteins (MAPs) promote the assembly of microtubules from purified tubulin in vitro. In order to establish a model system for the investigation of the role of MAPs in microtubule assembly in vivo, we have generated Saccharomyces cerevisiae strains that permit the modulation of the expression levels of MHP1 (MAP-Homologous Protein 1) and of the alpha and beta-tubulin genes...

Vincristine (VCR) accumulation in chronic lymphatic leukemia of B-cell origin (B-CLL) has recently been shown not to be inversely correlated to P-glycoprotein (PGP) levels. Therefore, we studied, in addition to PGP expression and accumulation of VCR, the cellular beta-tubulin content in quiescent and rhIL-2 activated B-CLL cells. VCR mediates cytotoxicity by binding to tubulin. Constitutive bet...

To determine the spectrum of tubulin variants in cytoskeletons of Trypanosoma brucei carboxy-terminal fragments of alpha- and beta-tubulin were isolated and characterized by sequencing and mass spectrometry. All variants arise by posttranslational modifications. We confirm the presence of tyrosinated and detyrosinated alpha-tubulin. Unexpectedly, but in line with its sequence, beta-tubulin also...

Virtually all animal cells rapidly and specifically depress synthesis of new alpha- and beta-tubulin polypeptides in response to microtubule inhibitors that increase the pool of depolymerized subunits, or in response to direct elevation of the cellular tubulin subunit content through microinjection of exogenous tubulin subunits. Collectively, these previous findings have documented the presence...

We have examined the phosphorylation of cellular microtubule proteins during differentiation and neurite outgrowth in N115 mouse neuroblastoma cells. N115 differentiation, induced by serum withdrawal, is accompanied by a fourfold increase in phosphorylation of a 54,000-mol-wt protein identified as a specific isoform of beta-tubulin by SDS PAGE, two-dimensional isoelectric focusing/SDS PAGE, and...