Identification and characterization of two novel proteins affecting fission yeast gamma-tubulin complex function

• Published in: Molecular biology of the cell 2004-05, Vol.15 (5), p.2287-2301
• Main Authors: Venkatram, Srinivas, Tasto, Joseph J, Feoktistova, Anna, Jennings, Jennifer L, Link, Andrew J, Gould, Kathleen L
• Format: Article
• Language: English
• Subjects: Binding Sites; Calmodulin-Binding Proteins - analysis; Calmodulin-Binding Proteins - genetics; Calmodulin-Binding Proteins - metabolism; Cell Division - genetics; Cell Division - physiology; Cell Polarity - genetics; Gene Deletion; Green Fluorescent Proteins; Intranuclear Space - ultrastructure; Microtubule-Associated Proteins - genetics; Microtubule-Associated Proteins - metabolism; Microtubule-Associated Proteins - physiology; Microtubule-Organizing Center - metabolism; Microtubule-Organizing Center - physiology; Microtubules - metabolism; Microtubules - physiology; Models, Biological; Molecular Sequence Data; Protein Interaction Mapping; Schizosaccharomyces - genetics; Schizosaccharomyces - metabolism; Schizosaccharomyces - ultrastructure; Schizosaccharomyces pombe; Schizosaccharomyces pombe Proteins - genetics; Schizosaccharomyces pombe Proteins - metabolism; Schizosaccharomyces pombe Proteins - physiology; Sequence Alignment; Spindle Apparatus - genetics; Spindle Apparatus - metabolism; Tubulin - metabolism
• ISSN: 1059-1524; 1939-4586; 1059-1524
• DOI: 10.1091/mbc.E03-10-0728

The gamma-tubulin complex, via its ability to organize microtubules, is critical for accurate chromosome segregation and cytokinesis in the fission yeast, Schizosaccharomyces pombe. To better understand its roles, we have purified the S. pombe gamma-tubulin complex. Mass spectrometric analyses of the purified complex revealed known components and identified two novel proteins (i.e., Mbo1p and Gfh1p) with homology to gamma-tubulin-associated proteins from other organisms. We show that both Mbo1p and Gfh1p localize to microtubule organizing centers. Although cells deleted for either mbo1(+) or gfh1(+) are viable, they exhibit a number of defects associated with altered microtubule function such as defects in cell polarity, nuclear positioning, spindle orientation, and cleavage site specification. In addition, mbo1Delta and gfh1Delta cells exhibit defects in astral microtubule formation and anchoring, suggesting that these proteins have specific roles in astral microtubule function. This study expands the known roles of gamma-tubulin complex components in organizing different types of microtubule structures in S. pombe.