Mzt1/Tam4, a fission yeast MOZART1 homologue, is an essential component of the γ-tubulin complex and directly interacts with GCP3(Alp6)

• Published in: Molecular biology of the cell 2013-11, Vol.24 (21), p.3337
• Main Authors: Dhani, Deepsharan K, Goult, Benjamin T, George, Gifty M, Rogerson, Daniel T, Bitton, Danny A, Miller, Crispin J, Schwabe, John W R, Tanaka, Kayoko
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Binding Sites - genetics; Blotting, Western; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Humans; Microscopy, Fluorescence; Microtubule-Associated Proteins - genetics; Microtubule-Associated Proteins - metabolism; Microtubule-Organizing Center - metabolism; Molecular Sequence Data; Protein Binding; Protein Subunits - genetics; Protein Subunits - metabolism; Schizosaccharomyces - genetics; Schizosaccharomyces - metabolism; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - metabolism; Sequence Homology, Amino Acid; Tubulin - genetics; Tubulin - metabolism; Two-Hybrid System Techniques
• ISSN: 1939-4586; 1939-4586
• DOI: 10.1091/mbc.E13-05-0253

In humans, MOZART1 plays an essential role in mitotic spindle formation as a component of the γ-tubulin ring complex. We report that the fission yeast homologue of MOZART1, Mzt1/Tam4, is located at microtubule-organizing centers (MTOCs) and coimmunoprecipitates with γ-tubulin Gtb1 from cell extracts. We show that mzt1/tam4 is an essential gene in fission yeast, encoding a 64-amino acid peptide, depletion of which leads to aberrant microtubule structure, including malformed mitotic spindles and impaired interphase microtubule array. Mzt1/Tam4 depletion also causes cytokinesis defects, suggesting a role of the γ-tubulin complex in the regulation of cytokinesis. Yeast two-hybrid analysis shows that Mzt1/Tam4 forms a complex with Alp6, a fission yeast homologue of γ-tubulin complex protein 3 (GCP3). Biophysical methods demonstrate that there is a direct interaction between recombinant Mzt1/Tam4 and the N-terminal region of GCP3(Alp6). Together our results suggest that Mzt1/Tam4 contributes to the MTOC function through regulation of GCP3(Alp6).