Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the sensory fibers of the rat sciatic nerve (fibers of the dorsal root ganglion cells), two components of tubulin transport were observed that differed in the rate of transport, solubility in Triton, and subunit composition. The faster component, migrating ahead of the neurofilament proteins, was soluble in 1% Triton. The slower component, migrating with the neurofilament proteins, was insoluble in 1% Triton and contained a unique polypeptide, "NAP," in the tubulin region that was not present in the faster component. "NAP" was not a subspecies of tubulin as evidenced by peptide mapping. It seems to be a neurofilament-associated protein. When a complete separation of the main tubulin wave from the neurofilament wave was achieved in the motor axons of the same nerve (axons of the ventral motoneurons) under the effect of beta,beta'-iminodipropionitrile, a portion of tubulin was still found associated with the retarded neurofilament wave. The subunit composition of this portion was similar to the slower, neurofilament-associated component in the sensory fibers under normal conditions, i.e., enriched in "NAP" and the most acidic subtype of beta-tubulin. It is suggested that two populations of transported tubulin exist that are differentiated by the extent of their interaction with neurofilaments.
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PMID:Two populations of axonally transported tubulin differentiated by their interactions with neurofilaments. 620 24

A fraction of chromaffin granule membranes contained a number of substrates for endogenous protein kinase activity as well as endogenous phosphatase activity. The major 32P-labelled polypeptide of molecular weight 43,000 appeared to be the alpha-subunit of pyruvate dehydrogenase of residual mitochondria. Several polypeptides showed cyclic AMP stimulation of phosphorylation of which the major polypeptide of molecular weight 59,000 shows half-maximal phosphorylation with 0.49 microM cyclic AMP. The phosphorylation of several other polypeptides is inhibited at high cyclic AMP concentrations. From studies with immunoprecipitation and two-dimensional electrophoresis it was found that alpha- and beta-tubulin and actin were absent from the granule membranes. However 32P labelling of a proportion of the copies of dopamine-beta-hydroxylase was demonstrated. The majority of the substrates for endogenous protein kinase activity are probably on the cytoplasmic side of the granule membrane.
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PMID:Phosphoproteins of the adrenal chromaffin granule membrane. 628 73

Mutations in a cell-cycle gene NDA2 of Schizosaccharomyces pombe have pleiotropic effects on nuclear division, nuclear location, and thiabendazole sensitivity ( Toda et al., 1983). By transformation and nucleotide sequence determination, we identified NDA2 as one of two alpha-tubulin genes present in the genome of S. pombe. Two cloned sequences complemented cold-sensitive and thiabendazole-supersensitive nda2 mutations; one was derived from NDA2 that encodes alpha 1-tubulin, the other from an unidentified locus encoding alpha 2-tubulin. The predicted amino acid sequences showed that the alpha 1- and alpha 2-tubulins had respective residues of 455 and 449 (molecular weights 51,200 and 50,600). The homology to porcine alpha-tubulin was 76% in both cases. Frequent alterations took place in the two restricted regions. The alpha 1-tubulin (NDA2) clone had a 90 bp intervening sequence, the alpha 2-tubulin clone did not. RNA blot hybridization experiments indicated that both genes are transcribed. S. pombe tubulin was isolated by cycles of assembly and disassembly. Presumed alpha- and beta-tubulin polypeptide bands reacted with monoclonal antibodies specific for chicken alpha- and beta-tubulins.
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PMID:Identification of the pleiotropic cell division cycle gene NDA2 as one of two different alpha-tubulin genes in Schizosaccharomyces pombe. 632 53

The complete sequence of a functionally expressed human beta-tubulin gene (5 beta) is presented. The amino acid sequence encoded by this gene constitutes a distinct isotype, differing from a previously described human beta-tubulin sequence at 21 positions throughout the polypeptide chain. The beta-tubulin coding sequence in 5 beta is interrupted by three intervening sequences of 1014, 117 and 4826 nucleotides. The largest of these contains ten members of the Alu family of middle repetitive sequences. Together, these regions account for sixty percent of this intervening sequence. Two of the Alu elements are juxtaposed head to tail, and share the same flanking direct repeat. The ten Alu sequences are substantially divergent, both from each other and from an Alu consensus sequence, and several contain deletions of up to half the entire sequence.
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PMID:Sequence of an expressed human beta-tubulin gene containing ten Alu family members. 646 17

The nucleotide sequence of a chicken genomic DNA segment containing the chicken beta 4 tubulin gene has been determined. The predicted amino acid sequence of beta 4 is surprisingly divergent from that of the chicken beta 2 gene that encodes the dominant neural beta tubulin. beta 4 differs from beta 2 at 36 residue positions and encodes a polypeptide that is four amino acids longer, yielding a divergence of 8.9% between the two beta tubulin isotypes. While many of the amino acid substitutions are conservative, several involve significant alteration in the physiochemical properties of the residue. Furthermore, the amino acid substitution positions are not randomly located within the primary sequence but are distinctly clustered: major divergence occurs in the carboxy-terminal region beyond residue 430 and within the second protein coding exon segments of the genes. In addition, large regions of absolute sequence conservation are also present. Certain sequences within the heterogeneous regions are conserved in other species, indicating that these regions are under positive evolutionary selection pressure and are therefore probably essential for some aspect of beta-tubulin function. These findings strongly suggest that regional amino acid sequence heterogeneity may play an important role in the establishment of functionally differentiated beta tubulin polypeptides.
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PMID:Sequence of a highly divergent beta tubulin gene reveals regional heterogeneity in the beta tubulin polypeptide. 649 Jul 18

The interphase cell of Crithidia fasciculata has three discrete tubulin populations: the subpellicular microtubules, the axonemal microtubules, and the nonpolymerized cytoplasmic pool protein. These three tubulin populations were independently and selectively purified, yielding, in each case, microtubule protein capable of self-assembly. All three preparations polymerized to form ribbons and sheets rather than the more usual microtubular structures. Analyses of the tubulin by two-dimensional polyacrylamide gel electrophoresis, isoelectric focusing, and peptide mapping indicated that the beta-tubulin complex remained constant regardless of source but that some heterogeneity was present in the alpha subunit. Cytoplasmic pool alpha tubulins (alpha 1/alpha 2) were the only alpha isotypes in the cytoplasm and also formed most of the alpha tubulin species in the pellicular fraction. Flagellar alpha tubulin (alpha 3) was the sole alpha isotype in the flagella; it appeared in small amounts in the pellicular fraction but was completely absent from the cytoplasm. In vitro translation products from polyadenylated RNA from C. fasciculata were also examined by two-dimensional polyacrylamide gel electrophoresis and possessed a protein corresponding to alpha 1/alpha 2 tubulin but lacked any alpha 3 tubulin. The alpha 3 polypeptide arose from a post-translational modification of a precursor polypeptide not identifiable by two-dimensional polyacrylamide gel electrophoresis as alpha 3. Peptide mapping data indicated that cytoplasmic alpha tubulin is the most likely precursor. These results demonstrate alpha-tubulin heterogeneity in this organism and also how close the relationship between flagellar and cytoskeletal tubulins can be among lower eucaryotes.
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PMID:Tubulin heterogeneity in the trypanosome Crithidia fasciculata. 671 41

The polypeptides synthesized during the cell cycle of HeLa cells were analyzed by means of two-dimensional gel electrophoresis followed by fluorography under conditions in which the position of 700 polypeptides (acidic and basic) could be reproducibly assessed. Mitotic cells obtained by mechanical detachment and synchronized cells in other stages of the cell cycle were labeled with [35S]methionine for 30-min pulses or for long terms starting at the beginning of each phase. Visual comparison of the polypeptide maps obtained in the different stages of the cell cycle showed that these were strikingly similar, and there was no indication that the synthesis of any of the detected polypeptides was confined to only one of the cell cycle phases. Quantitation of 99 abundant polypeptides (acidic and basic) in pulse-labeled and long-term labeled cells revealed that the relative amount (i.e., the rate of synthesis) of most polypeptides, including total actin, alpha-actinin, 6 abundant basic nonhistone proteins, and 13 major acidic proteins present in Triton cytoskeletons, remains constant throughout the cell cycle. Among the few variable polypeptides (markers), we have identified alpha- and beta-tubulin (increase in M), the subunit of the 100-A filament protein "fibroblast type" (decreases in M), and a 36,000 mol wt acidic cytoarchitectural protein that increases in S. A few other unidentified polypeptides have also been found to vary in M and in M and G2, but no marker was found in G1.
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PMID:A search for differential polypeptide synthesis throughout the cell cycle of HeLa cells. 689 40

The polypeptide composition of cytoplasts and karyoplasts prepared form HeLa cells prelabelled with [35S]-methionine and enucleated with Cytochalasin B has been analyzed using high resolution two dimensional gel electrophoresis (IEF and NEPHGE). Of the 259 major proteins followed in this study we have identified 73 polypeptides (30 acidic(IEF) and 43 basic (NEPHGE)) that are present mainly in karyoplasts. One of these polypeptides (IEF 49) has previously been shown to be a polypeptide marker for cycling cells. A total of 59 polypeptides (27 acidic and 32 basic) were found to be present mainly in cytoplasts. Many polypeptides (109 acidic and 18 basic) including Y and beta-actin (60% in cytoplasts), beta-tubulin (60% in cytoplasts), vimentin (75% in cytoplasts) and alpha-actinin (65% in cytoplasts) were found to be present in both cellular fragments. These results could be of value in assigning the cellular distribution of potential regulatory proteins.
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PMID:Distribution of HeLa cells polypeptides in cytoplasts and karyoplasts. 723 77

[35S]Methionine labelled polypeptides from mouse CLID, hamster ovary cells (CHO, and 7 derived somatic cell hybrids which have segregated CHO chromosomes, were analysed by means of high resolution two-dimensional gel electrophoresis under conditions in which the position of 600 polypeptides could be reproducibly assessed. As judged from the two-dimensional gel electrophoretic patterns (isoelectric focussing (IEF) and non-equilibrium pH gradient electrophoresis (NEPHGE)) gene expression in all the hybrids resembled the mouse CLID parent and with only one exception they all expressed different numbers and intensities of CHO specific polypeptides. Even though some of the hybrids expressed as much as 50% of the total number of CHO specific polypeptides that could be clearly differentiated from those of the mouse parent we failed to find a direct correlation between the expression of any given CHO polypeptide and the morphological or tumorigenic properties of the hybrids. Most CHO specific polypeptides, however, were expressed at lower levels in the hybrids as compared to the parent CHO cells, a fact that may be due to the chromosomal constitution of the hybrids, regulation or both. Similarly, the quantitation of the major cytoskeletal polypeptides present in the hybrids, such as alpha-and beta-tubulin, vimentin, total actin and 3 polypeptides (IEF 12, 24 and 31) present in intermediate filament enriched cytoskeletons, indicate that changes in the relative proportion of any of these proteins is not sufficient to account for the morphology, actin microfilament pattern or tumorigenicity of the hybrids. Co-expression of cytoskeletal proteins in the hybrids could only be demonstrated in the case of the related mouse IEF 24 and hamster IEF 7 polypeptides. In all other cases the cytoskeletal polypeptides co-migrated and presented similar one-dimensional peptide maps. Some principles are emerging concerning the possibility of using somatic cell hybridization in combination with two-dimensional gel electrophoresis to locate genes coding for particular polypeptides on a given chromosome.
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PMID:Gene expression in murine hybrids exhibiting different morphologies and tumorigenic properties. 728 83

Although Ustilago maydis is readily amenable to molecular genetic experimentation, few antibiotic-resistance markers are available for DNA-mediated transformation. This poses constraints on experiments involving targeted gene disruption and complementation. To address this problem, we constructed vectors using one of three additional genes as dominant selectable markers for transformation. Two genes, sat-1 (encoding streptothricin acetyltransferase) and Sh-ble (encoding a phleomycin-resistance polypeptide), are of bacterial origin and have been engineered for expression in Ustilago sp. The third gene encodes an allele of U. maydis beta-tubulin that confers resistance to the fungicide benomyl.
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PMID:Three selectable markers for transformation of Ustilago maydis. 751 16


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