The axonal transport of the diverse isotubulins in the motor axons of the rat sciatic nerve was studied by two-dimensional polyacrylamide gel electrophoresis after intraspinal injection of [35S]methionine. 3 wk after injection, the nerve segments carrying the labeled axonal proteins of the slow components a (SCa) and b (SCb) of axonal transport were homogenized in a cytoskeleton-stabilizing buf...

Approaches which eliminate mRNA expression directly are ideally suited for reverse genetics applications in eukaryotic microbes which are asexual diploids, such as the protozoan parasite Leishmania. RNA interference (RNAi) approaches have been successful in many species, including the related parasite Trypanosoma brucei. For RNAi tests in Leishmania, we developed improved protocols for transien...

Self-digestion of cytoplasmic components is the hallmark of autophagic programmed cell death. This auto-degradation appears to be distinct from what occurs in apoptotic cells that are engulfed and digested by phagocytes. Although much is known about apoptosis, far less is known about the mechanisms that regulate autophagic cell death. Here we show that autophagic cell death is regulated by ster...

The polymerization of alpha- and beta-tubulin into microtubules results in a complex network of microfibrils that have important structural and functional roles in all eukaryotic cells. In addition, microtubules can interact with a diverse family of polypeptides which are believed to directly promote the assembly of microtubules and to modulate their functional activity. We have demonstrated th...

A compilation of intron positions obtained from a large number of eukaryotic genomes across orthologous tubulins is explored for molecular evolution. Comparison of intron positions for 41 alpha, 80 beta, and 30 gamma tubulin genomic sequences indicates that the putative ancestral tubulin gene contained at least 19, 33, and 52 intron positions distributed at different sites in the coding regions...

Polyglutamylation is a posttranslational modification of tubulin that is very common in neurons and ciliated or flagellated cells. It was proposed to regulate the binding of microtubule associated proteins (MAPs) and molecular motors as a function of the length of the polyglutamyl side-chain. Though much less common, this modification of tubulin also occurs in proliferating cells like HeLa cell...

Silent information regulator-2 (SIR2) proteins regulate lifespan of diverse organisms, but their distribution and roles in the CNS remain unclear. Here, we show that sirtuin 2 (SIRT2), a mammalian SIR2 homolog, is an oligodendroglial cytoplasmic protein and localized to the outer and juxtanodal loops in the myelin sheath. Among cytoplasmic proteins of OLN-93 oligodendrocytes, alpha-tubulin was ...

We have shown previously, using immunoelectron microscopy, that axonal microtubules (MTs) are composite, consisting of distinct domains that differ in their content of tyrosinated alpha-tubulin (tyr-tubulin). Here, we extend these studies using a novel preparation that permits visualization of individual axonal MTs over distances of several tens of micrometers using conventional immunofluoresce...

Two alpha-tubulin genes from the budding yeast Saccharomyces cerevisiae were identified and cloned by cross-species DNA homology. Nucleotide sequencing studies revealed that the two genes, named TUB1 and TUB3, encoded gene products of 447 and 445 amino acids, respectively, that are highly homologous to alpha-tubulins from other species. Comparison of the sequences of the two genes revealed a 19...