scholarly journals Tubulin interaction with kinetochore proteins: analysis by in vitro assembly and chemical cross-linking.

1987 ◽  
Vol 105 (2) ◽  
pp. 855-862 ◽  
Author(s):  
R D Balczon ◽  
B R Brinkley
Keyword(s):  
Protein Complexes ◽  
Chinese Hamster ◽  
Protein Band ◽  
Specific Protein ◽  
Microtubule Assembly ◽  
Cross Linking ◽  
Affinity Column ◽  
Metaphase Chromosomes ◽  
In Vitro Assembly

The sera from patients with the CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) variation of the autoimmune disease scleroderma contain autoantibodies that specifically recognize the kinetochore by immunofluorescence. Two major antigens of molecular masses 18 and 80 kD are consistently identified by Western blotting of proteins of isolated chromosomes using CREST sera. In this paper, the possible roles that these two proteins play in the interaction of metaphase chromosomes with tubulin and microtubules are examined using two different procedures. In one set of experiments. Chinese hamster ovary (CHO) chromosomes were extracted with 1-2 M NaCl before incubating with phosphocellulose-purified tubulin under in vitro microtubule assembly conditions. After this treatment, the kinetochores of the residual chromosome scaffolds can still initiate the in vitro assembly of microtubules. Immunoblots of the chromosome scaffold proteins demonstrate that the 18-kD protein has been solubilized by the 1-2 M NaCl extraction, suggesting that this protein is not essential for microtubule assembly at the kinetochore. In a second approach, tubulin was covalently cross-linked to kinetochores of CHO chromosomes using the reversible cross-linking reagent dithiobis (succinimidyl propionate). After DNase I digestion, the chromosomes were solubilized and subjected to anti-tubulin affinity chromatography. Tubulin-kinetochore protein complexes were specifically eluted and analyzed by PAGE and immunoblotting with scleroderma CREST serum. Only a small number of proteins were eluted from the antitubulin affinity column as shown by Coomassie Blue-stained gels. In addition to tubulin, an 80-kD polypeptide, bands at 110 and 24 kD, as well as a faint band at 54 kD, can be resolved. Several minor bands can also be seen in silver-stained gels. The 80-kD protein band from whole metaphase chromosomes reacted with scleroderma CREST serum by immunoblotting and therefore probably represents the major centromere antigen CENP-B. This report provides evidence for a specific protein complex on metaphase chromosomes that is contiguous with kinetochore-bound tubulin and may be involved in microtubule-kinetochore interactions during mitosis.

scholarly journals Microtubule Actin Cross-Linking Factor (Macf)

1999 ◽  
Vol 147 (6) ◽  
pp. 1275-1286 ◽  
Author(s):  
Conrad L. Leung ◽  
Dongming Sun ◽  
Min Zheng ◽  
David R. Knowles ◽  
Ronald K.H. Liem
Keyword(s):  
Calcium Binding ◽  
Coiled Coil ◽  
Specific Protein ◽  
Binding Domain ◽  
Full Length ◽  
Actin Binding ◽  
Cross Linking ◽  
Actin Binding Domain

We cloned and characterized a full-length cDNA of mouse actin cross-linking family 7 (mACF7) by sequential rapid amplification of cDNA ends–PCR. The completed mACF7 cDNA is 17 kb and codes for a 608-kD protein. The closest relative of mACF7 is the Drosophila protein Kakapo, which shares similar architecture with mACF7. mACF7 contains a putative actin-binding domain and a plakin-like domain that are highly homologous to dystonin (BPAG1-n) at its NH2 terminus. However, unlike dystonin, mACF7 does not contain a coiled–coil rod domain; instead, the rod domain of mACF7 is made up of 23 dystrophin-like spectrin repeats. At its COOH terminus, mACF7 contains two putative EF-hand calcium-binding motifs and a segment homologous to the growth arrest–specific protein, Gas2. In this paper, we demonstrate that the NH2-terminal actin-binding domain of mACF7 is functional both in vivo and in vitro. More importantly, we found that the COOH-terminal domain of mACF7 interacts with and stabilizes microtubules. In transfected cells full-length mACF7 can associate not only with actin but also with microtubules. Hence, we suggest a modified name: MACF (microtubule actin cross-linking factor). The properties of MACF are consistent with the observation that mutations in kakapo cause disorganization of microtubules in epidermal muscle attachment cells and some sensory neurons.

Mutation of the β1-tubulin gene associated with congenital macrothrombocytopenia affecting microtubule assembly

Blood ◽  
2009 ◽  
Vol 113 (2) ◽  
pp. 458-461 ◽  
Author(s):  
Shinji Kunishima ◽  
Ryoji Kobayashi ◽  
Tomohiko J. Itoh ◽  
Motohiro Hamaguchi ◽  
Hidehiko Saito
Keyword(s):  
Chinese Hamster ◽  
Microtubule Assembly ◽  
Nucleotide Polymorphism ◽  
Rare Disorders ◽  
Single Nucleotide ◽  
Normal Platelet ◽  
Peripheral Blood Cd34 ◽  
Cd34 Cells ◽  
In Vitro Transfection

Abstract Congenital macrothrombocytopenia is a genetically heterogeneous group of rare disorders. We identified the first TUBB1 mutation, R318W, in a patient with congenital macrothrombocytopenia. The patient was heterozygous for Q43P, but this single-nucleotide polymorphism (SNP) did not relate to macrothrombocytopenia. Although no abnormal platelet β1-tubulin localization/marginal band organization was observed, the level of β1-tubulin was decreased by approximately 50% compared with healthy controls. Large and irregular bleb protrusions observed in megakaryocytes derived from the patient's peripheral blood CD34+ cells suggested impaired megakaryocyte fragmentation and release of large platelets. In vitro transfection experiments in Chinese hamster ovary (CHO) cells demonstrated no incorporation of mutant β1-tubulin into microtubules, but the formation of punctuated insoluble aggregates. These results suggested that mutant protein is prone to aggregation but is unstable within megakaryocytes/platelets. Alternatively, mutant β1-tubulin may not be transported from the megakaryocytes into platelets. W318 β1-tubulin may interfere with normal platelet production, resulting in macrothrombocytopenia.

UV cross-linking identifies four polypeptides that require the TATA box to bind to the Drosophila hsp70 promoter

1990 ◽  
Vol 10 (8) ◽  
pp. 4233-4238
Author(s):  
D S Gilmour ◽  
T J Dietz ◽  
S C Elgin
Keyword(s):  
Specific Protein ◽  
Cross Linking ◽  
Dependent Manner ◽  
Hsp70 Promoter ◽  
Intimate Contact ◽  
Nuclear Extracts ◽  
Multicomponent Complex ◽  
Tata Sequence ◽  
Drosophila Embryos

A protein fraction that requires the TATA sequence to bind to the hsp70 promoter has been partially purified from nuclear extracts of Drosophila embryos. This TATA factor produces a large DNase I footprint that extends from -44 to +35 on the promoter. A mutation that changes TATA to TATG interferes both with the binding of this complex and with the transcription of the hsp70 promoter in vitro, indicating that this interaction is important for transcriptional activity. Using a highly specific protein-DNA cross-linking assay, we have identified four polypeptides that require the TATA sequence to bind to the hsp70 promoter. Polypeptides of 26 and 42 kilodaltons are in intimate contact with the TATA sequence. Polypeptides of 150 and 60 kilodaltons interact within the region from +24 to +47 in a TATA-dependent manner. Both the extended footprint and the polypeptides identified by UV cross-linking indicate that the Drosophila TATA factor is a multicomponent complex.

scholarly journals The Endogenous and Cell Cycle-dependent Phosphorylation of tau Protein in Living Cells: Implications for Alzheimer’s Disease

1998 ◽  
Vol 9 (6) ◽  
pp. 1495-1512 ◽  
Author(s):  
Susanne Illenberger ◽  
Qingyi Zheng-Fischhöfer ◽  
Ute Preuss ◽  
Karsten Stamer ◽  
Karlheinz Baumann ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Cell Cycle ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Chinese Hamster Ovary Cells ◽  
Phosphorylation Site ◽  
Chinese Hamster ◽  
Microtubule Assembly ◽  
Human Neuroblastoma

In Alzheimer’s disease the neuronal microtubule-associated protein tau becomes highly phosphorylated, loses its binding properties, and aggregates into paired helical filaments. There is increasing evidence that the events leading to this hyperphosphorylation are related to mitotic mechanisms. Hence, we have analyzed the physiological phosphorylation of endogenous tau protein in metabolically labeled human neuroblastoma cells and in Chinese hamster ovary cells stably transfected with tau. In nonsynchronized cultures the phosphorylation pattern was remarkably similar in both cell lines, suggesting a similar balance of kinases and phosphatases with respect to tau. Using phosphopeptide mapping and sequencing we identified 17 phosphorylation sites comprising 80–90% of the total phosphate incorporated. Most of these are in SP or TP motifs, except S214 and S262. Since phosphorylation of microtubule-associated proteins increases during mitosis, concomitant with increased microtubule dynamics, we analyzed cells mitotically arrested with nocodazole. This revealed that S214 is a prominent phosphorylation site in metaphase, but not in interphase. Phosphorylation of this residue strongly decreases the tau–microtubule interaction in vitro, suppresses microtubule assembly, and may be a key factor in the observed detachment of tau from microtubules during mitosis. Since S214 is also phosphorylated in Alzheimer’s disease tau, our results support the view that reactivation of the cell cycle machinery is involved in tau hyperphosphorylation.

scholarly journals Dynamic Localization of CLIP-170 to Microtubule Plus Ends Is Coupled to Microtubule Assembly

1999 ◽  
Vol 144 (1) ◽  
pp. 99-112 ◽  
Author(s):  
Georgios S. Diamantopoulos ◽  
Franck Perez ◽  
Holly V. Goodson ◽  
Gérard Batelier ◽  
Ronald Melki ◽  
...  
Keyword(s):  
Sedimentation Velocity ◽  
Microtubule Assembly ◽  
In Vitro Assays ◽  
Cross Linking ◽  
Tubulin Polymerization ◽  
Binding Properties ◽  
Dynamic Localization ◽  
Microtubule Binding

CLIP-170 is a cytoplasmic linker protein that localizes to plus ends of microtubules in vivo. In this study, we have characterized the microtubule-binding properties of CLIP-170, to understand the mechanism of its plus end targeting. We show that the NH2-terminal microtubule-interacting domain of CLIP-170 alone localizes to microtubule plus ends when transfected into cells. Association of CLIP-170 with newly-formed microtubules was observed in cells microinjected with biotinylated tubulin, used as a tracer for growing microtubules. Using in vitro assays, association of CLIP-170 with recently polymerized tubulin is also seen. Cross-linking and sedimentation velocity experiments suggest association of CLIP-170 with nonpolymerized tubulin. We conclude from these experiments that the microtubule end targeting of CLIP-170 is closely linked to tubulin polymerization.

scholarly journals UV cross-linking identifies four polypeptides that require the TATA box to bind to the Drosophila hsp70 promoter.

1990 ◽  
Vol 10 (8) ◽  
pp. 4233-4238 ◽  
Author(s):  
D S Gilmour ◽  
T J Dietz ◽  
S C Elgin
Keyword(s):  
Specific Protein ◽  
Cross Linking ◽  
Dependent Manner ◽  
Hsp70 Promoter ◽  
Intimate Contact ◽  
Nuclear Extracts ◽  
Multicomponent Complex ◽  
Tata Sequence ◽  
Drosophila Embryos

A protein fraction that requires the TATA sequence to bind to the hsp70 promoter has been partially purified from nuclear extracts of Drosophila embryos. This TATA factor produces a large DNase I footprint that extends from -44 to +35 on the promoter. A mutation that changes TATA to TATG interferes both with the binding of this complex and with the transcription of the hsp70 promoter in vitro, indicating that this interaction is important for transcriptional activity. Using a highly specific protein-DNA cross-linking assay, we have identified four polypeptides that require the TATA sequence to bind to the hsp70 promoter. Polypeptides of 26 and 42 kilodaltons are in intimate contact with the TATA sequence. Polypeptides of 150 and 60 kilodaltons interact within the region from +24 to +47 in a TATA-dependent manner. Both the extended footprint and the polypeptides identified by UV cross-linking indicate that the Drosophila TATA factor is a multicomponent complex.

Inability to detect Chlamyodomonas microtubule assembly in vitro: possible implications to the in vivo regulation of microtubule assembly

1975 ◽  
Vol 17 (3) ◽  
pp. 669-681
Author(s):  
K.W. Farrell ◽  
R.G. Burns
Keyword(s):  
Column Chromatography ◽  
Divalent Cation ◽  
Microtubule Assembly ◽  
Mammalian Brain ◽  
Wide Range ◽  
In Vitro Assembly ◽  
Brain Extracts ◽  
Brain Tubulin

It has been demonstrated that the in vitro assembly of microtubules from Chlamydomonas preparations does not occur under a wide range of conditions, including those efficacious for mammalian brain tubulin. This incompetence of Chlamydomonas extracts to form microtubules is independent of the tubulin concentration, the presence of added nucleotides or an added seed, temperature, or the concentration of divalent cation. However, an amorphous aggregate was observed under certain conditions, who composition was mainly tubulin. The in vitro reassembly of microtubules in gerbil brain extracts is inhibited by Chlamydomonas preparations. Fractionation of the Chlamydomonas extracts by column chromatography suggests that the inhibitory component is Chlamydomonas tubulin itself. The mechanism of this inhibition is unknown, but reassembly experiments indicate that the 2 types of tubulins cannot copolymerize. We suggest that the Chlamydomonas tubulin, derived from a cytoplasmic pool, requires to be activated prior to its in vivo polymerization into microtubules.

Microtubule associated proteins in microtubule preparations made with and without glycerol

1984 ◽  
Vol 62 (9) ◽  
pp. 803-813 ◽  
Author(s):  
Robert A. B. Keates
Keyword(s):  
Binding Assay ◽  
Critical Concentration ◽  
Brain Homogenate ◽  
Microtubule Assembly ◽  
Microtubule Associated Proteins ◽  
In Vitro Assembly ◽  
Microtubule Protein ◽  
Associated Proteins ◽  
The Difference

Preparation of microtubule protein in the presence or absence of glycerol results in differences in polymerization properties and content of microtubule associated proteins. The variation in properties appears to result from the reduced proportion of microtubule associated proteins in preparations made with glycerol. I have used the colchicine binding assay to monitor recovery of active tubulin and have found that a single factor can account for the difference. During the in vitro assembly of microtubules from the crude brain homogenate, glycerol promotes polymerization of the bulk of the tubulin, while less than half is incorporated into microtubules in the absence of glycerol. Assembly of partly purified microtubule protein is not enhanced by glycerol however. Microtubule associated proteins present in the crude homogenate are almost completely incorporated into the microtubules regardless of the presence of glycerol, and their high content in glycerol-free preparations appears to be the trivial result of low tubulin recovery. The high affinity of microtubule associated proteins for the assembled microtubules has other consequences for in vitro studies of microtubule assembly, and critical concentration plots to determine the polymerization equilibrium constant can be distorted unless the preparation used has a high content of microtubule associated proteins.

scholarly journals The RNA polymerase factory: a robotic in vitro assembly platform for high-throughput production of recombinant protein complexes

2007 ◽  
Vol 36 (1) ◽  
pp. 245-252 ◽  
Author(s):  
Sven Nottebaum ◽  
Lin Tan ◽  
Dominika Trzaska ◽  
Hannah C. Carney ◽  
Robert O. J. Weinzierl
Keyword(s):  
Recombinant Protein ◽  
Rna Polymerase ◽  
High Throughput ◽  
Protein Complexes ◽  
In Vitro Assembly
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