title: The spindle matrix protein, Chromator, is a novel tubulin binding protein that can interact with both microtubules and free tubulin.
abstract: The chromodomain protein, Chromator, is localized to chromosomes during interphase; however, during cell division together with other nuclear proteins Chromator redistributes to form a macro molecular spindle matrix complex that embeds the microtubule spindle apparatus. It has been demonstrated that the CTD of Chromator is sufficient for localization to the spindle matrix and that expression of this domain alone could partially rescue Chro mutant microtubule spindle defects. Furthermore, the presence of frayed and unstable microtubule spindles during mitosis after Chromator RNAi depletion in S2 cells indicated that Chromator may interact with microtubules. In this study using a variety of biochemical assays we have tested this hypothesis and show that Chromator not only has binding activity to microtubules with a Kd of 0.23 µM but also to free tubulin. Furthermore, we have mapped the interaction with microtubules to a relatively small stretch of 139 amino acids in the carboxy-terminal region of Chromator. This sequence is likely to contain a novel microtubule binding interface since database searches did not find any sequence matches with known microtubule binding motifs.
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Changfu
authors: C
authors: Yao
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Chao
authors: C
authors: Wang
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Yeran
authors: Y
authors: Li
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Yun
authors: Y
authors: Ding
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Uttama
authors: U
authors: Rath
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Saheli
authors: S
authors: Sengupta
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Jack
authors: J
authors: Girton
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Kristen M
authors: KM
authors: Johansen
authors: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa, United States of America.
authors: Jørgen
authors: J
authors: Johansen
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000378:metabolism; D000906:Antibodies / Q000276:immunology; D029721:Drosophila Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism; D047468:Immunoprecipitation; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D034521:Nuclear Matrix-Associated Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D014404:Tubulin / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*
chemical_list: D000906:Antibodies; C498868:Chro protein, Drosophila; D029721:Drosophila Proteins; D034521:Nuclear Matrix-Associated Proteins; D014404:Tubulin