A new tubulin-binding protein

1982 ◽  
Vol 106 (3) ◽  
pp. 704-710 ◽  
Author(s):  
Nirbhay Kumar ◽  
Martin Flavin
Keyword(s):  
Binding Protein ◽  
Tubulin Binding

scholarly journals The growth-related, translationally controlled protein P23 has properties of a tubulin binding protein and associates transiently with microtubules during the cell cycle

1999 ◽  
Vol 112 (8) ◽  
pp. 1257-1271 ◽  
Author(s):  
Y. Gachet ◽  
S. Tournier ◽  
M. Lee ◽  
A. Lazaris-Karatzas ◽  
T. Poulton ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Mutational Analysis ◽  
Binding Protein ◽  
Binding Domain ◽  
Dependent Manner ◽  
Cell Extracts ◽  
Tubulin Binding ◽  
Cycle Dependent ◽  
Almost All

The translationally controlled protein P23 was discovered by the early induction of its rate of synthesis after mitogenic stimulation of mouse fibroblasts. P23 is expressed in almost all mammalian tissues and it is highly conserved between animals, plants and yeast. Based on its amino acid sequence, P23 cannot be attributed to any known protein family, and its cellular function remains to be elucidated. Here, we present evidence that P23 has properties of a tubulin binding protein that associates with microtubules in a cell cycle-dependent manner. (1) P23 is a cytoplasmic protein that occurs in complexes of 100–150 kDa, and part of P23 can be immunoprecipitated from HeLa cell extracts with anti-tubulin antibodies. (2) In immunolocalisation experiments we find P23 associated with microtubules during G1, S, G2 and early M phase of the cell cycle. At metaphase, P23 is also bound to the mitotic spindle, and it is detached from the spindle during metaphase-anaphase transition. (3) A GST-P23 fusion protein interacts with alpha- and beta-tubulin, and recombinant P23 binds to taxol-stabilised microtubules in vitro. The tubulin binding domain of P23 was identified by mutational analysis; it shows similarity to part of the tubulin binding domain of the microtubule-associated protein MAP-1B. (4) Overexpression of P23 results in cell growth retardation and in alterations of cell morphology. Moreover, elevation of P23 levels leads to microtubule rearrangements and to an increase in microtubule mass and stability.

RanBP10 Is a Cytoplasmic GDP/GTP Exchange Factor That Modulates Microtubule Dynamics in Late Megakaryocytes.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 738-738
Author(s):  
Harald Schulze ◽  
Marei Dose ◽  
Manav Korpal ◽  
Joseph E. Italiano ◽  
Ramesh A. Shivdasani
Keyword(s):  
Binding Protein ◽  
Blood Platelets ◽  
Nucleotide Exchange ◽  
Exchange Factor ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factor ◽  
Tubulin Binding ◽  
Organizing Center ◽  
Mammalian Genomes ◽  
Β Tubulin

Abstract Megakaryocytes are large cells within the bone marrow that undergo complex fragmentation to release up to thousands of virtually identical blood platelets into the periphery. Each platelet contains a characterisitic microtubule (MT) marginal band that is derived from MT filaments present in long protrusion-like intermediate structures, designated proplatelets, that are immediate precursors of platelets. These MT filaments are generated in the MK periphery, where they require massive mobilization that is supposed to be different from either normal interphase MT nucleation that commonly depends on γ-tubulin in the MT-organizing center. or from MTs in the mitotic spindle that require Ran·GTP, which is generated along condensed chromosomes by the chromatin-asociated guanine nucleotide exchange factor (GEF) RCC1. We first demonstrated that γ-tubulin is absent in most of the mature or proplatelet-forming MKs, where it is therefore unlikely to attribute to the total MT nucleation. MTs are tubular cytoskeletal structures that contain polymerized α- or β-tubulin subunits. Mammalian genomes share 5–6 β-tubulin isotypes of which β1-tubulin is the most divergent, especially in its C-terminal domain. β1-tubulin expression is restricted to late MKs and platelets, where it accounts for most of the β-tubulin in MT filaments. Its ablation in the mouse results in thrombocytopenia, spherocytosis and attenuated platelet function. We therefore sought to identify proteins that bind to β1-tubulin and performed a yeast two-hybrid screen using a MK-derived cDNA library. We identified a cytoplasmic Ran-binding protein, RanBP10, as a factor that associates with cellular MTs and unexpectedly harbors GEF activity toward Ran. Loss of RanBP10 in cultured MKs disrupts MT organization and its overexpression drives accumulation of extranuclear Ran and assembly of thick and abnormally long MTs. RanBP10 thus functions as a localized β-tubulin binding protein that harbors GEF activity toward Ran in the cytoplasm, much like RCC1 in the nucleus. Our results suggest that spatiotemporally restricted generation of Ran·GTP in the cytoplasm organizes specialized MTs required for thrombopoiesis and that RanBP10 provides a molecular link between Ran and non-centrosomal MTs.

scholarly journals Polyglutamylated Tubulin Binding Protein C1orf96/CSAP Is Involved in Microtubule Stabilization in Mitotic Spindles

PLoS ONE ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. e0142798 ◽  
Author(s):  
Shinya Ohta ◽  
Mayako Hamada ◽  
Nobuko Sato ◽  
Iyo Toramoto
Keyword(s):  
Binding Protein ◽  
Mitotic Spindles ◽  
Microtubule Stabilization ◽  
Tubulin Binding

scholarly journals Phosphorylation of the tubulin-binding protein, stathmin, by Cdk5 and MAP kinases in the brain

2006 ◽  
Vol 99 (1) ◽  
pp. 237-250 ◽  
Author(s):  
Kanehiro Hayashi ◽  
Yong Pan ◽  
Hongjun Shu ◽  
Toshio Ohshima ◽  
Janice W. Kansy ◽  
...  
Keyword(s):  
Map Kinases ◽  
Binding Protein ◽  
Tubulin Binding ◽  
The Brain

Regulation of tubulin polypeptides and microtubule function: Rki1p interacts with the β-tubulin binding protein Rbl2p

Chromosoma ◽  
1998 ◽  
Vol 107 (6-7) ◽  
pp. 471-478 ◽  
Author(s):  
Adelle M. Smith ◽  
Julie E. Archer ◽  
Frank Solomon
Keyword(s):  
Binding Protein ◽  
Tubulin Binding ◽  
Microtubule Function ◽  
Β Tubulin

Function of Tubulin Binding Proteins in Vivo

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 69-80 ◽  
Author(s):  
James A Fleming ◽  
Leticia R Vega ◽  
Frank Solomon
Keyword(s):  
Binding Proteins ◽  
Binding Protein ◽  
Yeast Cells ◽  
Gene Products ◽  
Salvage Pathway ◽  
Tubulin Binding ◽  
Mutant Cells ◽  
Β Tubulin

Abstract Overexpression of the β-tubulin binding protein Rbl2p/cofactor A is lethal in yeast cells expressing a mutant α-tubulin, tub1-724, that produces unstable heterodimer. Here we use RBL2 overexpression to identify mutations in other genes that affect formation or stability of heterodimer. This approach identifies four genes—CIN1, CIN2, CIN4, and PAC2—as affecting heterodimer formation in vivo. The vertebrate homologues of two of these gene products—Cin1p/cofactor D and Pac2p/cofactor E—can catalyze exchange of tubulin polypeptides into preexisting heterodimer in vitro. Previous work suggests that both Cin2p or Cin4p act in concert with Cin1p in yeast, but no role for vertebrate homologues of either has been reported in the in vitro reaction. Results presented here demonstrate that these proteins can promote heterodimer formation in vivo. RBL2 overexpression in cin1 and pac2 mutant cells causes microtubule disassembly and enhanced formation of Rbl2p-β-tubulin complex, as it does in the α-tubulin mutant that produces weakened heterodimer. Significantly, excess Cin1p/cofactor D suppresses the conditional phenotypes of that mutant α-tubulin. Although none of the four genes is essential for viability under normal conditions, they become essential under conditions where the levels of dissociated tubulin polypeptides increase. Therefore, these proteins may provide a salvage pathway for dissociated tubulin heterodimers and so rescue cells from the deleterious effects of free β-tubulin.

scholarly journals The Spindle Matrix Protein, Chromator, Is a Novel Tubulin Binding Protein That Can Interact with Both Microtubules and Free Tubulin

PLoS ONE ◽  
2014 ◽  
Vol 9 (7) ◽  
pp. e103855 ◽  
Author(s):  
Changfu Yao ◽  
Chao Wang ◽  
Yeran Li ◽  
Yun Ding ◽  
Uttama Rath ◽  
...  
Keyword(s):  
Matrix Protein ◽  
Binding Protein ◽  
Spindle Matrix ◽  
Tubulin Binding

Tubulin Binding, Protein-Bound Conformation in Solution, and Antimitotic Cellular Profiling of Noscapine and Its Derivatives

2012 ◽  
Vol 55 (5) ◽  
pp. 1920-1925 ◽  
Author(s):  
Youssef L. Bennani ◽  
Wenxin Gu ◽  
Angeles Canales ◽  
Fernando J. Dı́az ◽  
Brenda K. Eustace ◽  
...  
Keyword(s):  
Binding Protein ◽  
Tubulin Binding

scholarly journals Protection from Free β-Tubulin by the β-Tubulin Binding Protein Rbl2p

2002 ◽  
Vol 22 (1) ◽  
pp. 138-147 ◽  
Author(s):  
Katharine C. Abruzzi ◽  
Adelle Smith ◽  
William Chen ◽  
Frank Solomon
Keyword(s):  
Binding Protein ◽  
In Vitro Assay ◽  
In Vitro Studies ◽  
Microtubule Assembly ◽  
Vitro Assay ◽  
Tubulin Binding ◽  
And Function ◽  
Β Tubulin ◽  
In Cells

ABSTRACT Free β-tubulin not in heterodimers with α-tubulin can be toxic, disrupting microtubule assembly and function. We are interested in the mechanisms by which cells protect themselves from free β-tubulin. This study focused specifically on the function of Rbl2p, which, like α-tubulin, can rescue cells from free β-tubulin. In vitro studies of the mammalian homolog of Rbl2p, cofactor A, have suggested that Rbl2p/cofactor A may be involved in tubulin folding. Here we show that Rbl2p becomes essential in cells containing a modest excess of β-tubulin relative to α-tubulin. However, this essential activity of Rbl2p/cofactorA does not depend upon the reactions described by the in vitro assay. Rescue of β-tubulin toxicity requires a minimal but substoichiometric ratio of Rbl2p to β-tubulin. The data suggest that Rbl2p binds transiently to free β-tubulin, which then passes into an aggregated form that is not toxic.

scholarly journals Modulation of Tubulin Polypeptide Ratios by the Yeast Protein Pac10p

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 857-864 ◽  
Author(s):  
Pablo Alvarez ◽  
Adelle Smith ◽  
James Fleming ◽  
Frank Solomon
Keyword(s):  
Cell Death ◽  
Cell Growth ◽  
Binding Protein ◽  
Genetic Alterations ◽  
Significant Excess ◽  
Yeast Protein ◽  
Tubulin Gene ◽  
Tubulin Binding ◽  
And Function ◽  
Β Tubulin

Abstract Normal assembly and function of microtubules require maintenance of the proper levels of several proteins, including the tubulin polypeptides themselves. For example, in yeast a significant excess of β-tubulin causes rapid microtubule disassembly and subsequent cell death. Even the modest excess of β-tubulin produced by genetic alterations such as deletion of the minor α-tubulin gene TUB3 affects cell growth and can confer microtubule phenotypes. We show here that the levels of the yeast protein Pac10p affect the relative levels of the tubulin polypeptides. Cells deleted for PAC10 have the same phenotypes as do cells that express reduced levels of α-tubulin or Rbl2p, two proteins that bind β-tubulin. Conversely, overexpression of Pac10p enhances the ability of α-tubulin or Rbl2p to suppress the lethality associated with excess β-tubulin. However, Pac10p is itself not a β-tubulin binding protein. Pac10 null cells show a 30% decrease in the ratio of α-tubulin to β-tubulin. The results suggest that Pac10p modulates the level of α-tubulin in the cell, and so influences microtubule morphogenesis and tubulin metabolism.

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