Mto2p, a novel fission yeast protein required for cytoplasmic microtubule organization and anchoring of the cytokinetic actin ring.

Microtubules regulate diverse cellular processes, including chromosome segregation, nuclear positioning, and cytokinesis. In many organisms, microtubule nucleation requires gamma-tubulin and associated proteins present at specific microtubule organizing centers (MTOCs). In fission yeast, interphase cytoplasmic microtubules originate from poorly characterized interphase MTOCs and spindle pole body (SPB), and during late anaphase from the equatorial MTOC (EMTOC). It has been previously shown that Mto1p (Mbo1p/Mod20p) function is important for the organization/nucleation of all cytoplasmic microtubules. Here, we show that Mto2p, a novel protein, interacts with Mto1p and is important for establishing a normal interphase cytoplasmic microtubule array. In addition, mto2Delta cells fail to establish a stable EMTOC and localize gamma-tubulin complex members to this medial structure. As predicted from these functions, Mto2p localizes to microtubules, the SPB, and the EMTOC in an Mto1p-dependent manner. mto2Delta cells fail to anchor the cytokinetic actin ring in the medial region of the cell and under conditions that mildly perturb actin structures, these rings unravel in mto2Delta cells. Our results suggest that the Mto2p and the EMTOC are critical for anchoring the cytokinetic actin ring to the medial region of the cell and for proper coordination of mitosis with cytokinesis.

[1]  K. Sawin,et al.  Fission yeast mto2p regulates microtubule nucleation by the centrosomin-related protein mto1p. , 2005, Molecular biology of the cell.

[2]  T. G. Setty,et al.  Efficient formation of bipolar microtubule bundles requires microtubule-bound γ-tubulin complexes , 2005, The Journal of cell biology.

[3]  Jianhua Liu,et al.  The nuclear kinase Lsk1p positively regulates the septation initiation network and promotes the successful completion of cytokinesis in response to perturbation of the actomyosin ring in Schizosaccharomyces pombe. , 2004, Molecular biology of the cell.

[4]  M. Balasubramanian,et al.  The Clp1p/Flp1p phosphatase ensures completion of cytokinesis in response to minor perturbation of the cell division machinery in Schizosaccharomyces pombe , 2004, Journal of Cell Science.

[5]  S. Moreno,et al.  A role for the Cdc14-family phosphatase Flp1p at the end of the cell cycle in controlling the rapid degradation of the mitotic inducer Cdc25p in fission yeast , 2004, Journal of Cell Science.

[6]  K. Sawin,et al.  Microtubule Nucleation at Non-Spindle Pole Body Microtubule-Organizing Centers Requires Fission Yeast Centrosomin-Related Protein mod20p , 2004, Current Biology.

[7]  K. Gould,et al.  Identification and characterization of two novel proteins affecting fission yeast gamma-tubulin complex function. , 2004, Molecular biology of the cell.

[8]  K. Gould,et al.  Sid4p-Cdc11p Assembles the Septation Initiation Network and Its Regulators at the S. pombe SPB , 2004, Current Biology.

[9]  R. Daga,et al.  Rsp1p, a J domain protein required for disassembly and assembly of microtubule organizing centers during the fission yeast cell cycle. , 2004, Developmental cell.

[10]  K. Gould,et al.  Fission yeast Clp1p phosphatase affects G2/M transition and mitotic exit through Cdc25p inactivation , 2004, The EMBO journal.

[11]  M. Glotzer.  Cleavage furrow positioning , 2004, The Journal of cell biology.

[12]  S. Uzawa,et al.  Individual microtubule dynamics contribute to the function of mitotic and cytoplasmic arrays in fission yeast , 2003, Journal of Cell Science.

[13]  P. Nurse,et al.  Equatorial Retention of the Contractile Actin Ring by Microtubules During Cytokinesis , 2003, Science.

[14]  K. Gould,et al.  An anillin homologue, Mid2p, acts during fission yeast cytokinesis to organize the septin ring and promote cell separation , 2003, The Journal of cell biology.

[15]  M. Balasubramanian,et al.  Sterol-rich plasma membrane domains in the fission yeast Schizosaccharomyces pombe , 2003, Journal of Cell Science.

[16]  T. Toda,et al.  A Fourth Component of the Fission Yeast γ-Tubulin Complex, Alp16, Is Required for Cytoplasmic Microtubule Integrity and Becomes Indispensable When γ-Tubulin Function Is Compromised , 2002 .

[17]  K. Gould,et al.  The spindle pole body protein Cdc11p links Sid4p to the fission yeast septation initiation network. , 2002, Molecular biology of the cell.

[18]  T. Toda,et al.  The γ‐tubulin complex protein Alp4 provides a link between the metaphase checkpoint and cytokinesis in fission yeast , 2002, Genes to cells : devoted to molecular & cellular mechanisms.

[19]  T. Davis,et al.  Reconstitution and characterization of budding yeast gamma-tubulin complex. , 2002, Molecular biology of the cell.

[20]  M. Bornens.  Centrosome composition and microtubule anchoring mechanisms. , 2002, Current opinion in cell biology.

[21]  T. Toda,et al.  A fourth component of the fission yeast gamma-tubulin complex, Alp16, is required for cytoplasmic microtubule integrity and becomes indispensable when gamma-tubulin function is compromised. , 2002, Molecular biology of the cell.

[22]  T. Davis,et al.  Reconstitution and characterization of budding yeast gamma-tubulin complex. , 2002, Molecular biology of the cell.

[23]  I. Hagan,et al.  MTOC formation during mitotic exit in fission yeast. , 2001, Journal of cell science.

[24]  S. Schmidt,et al.  S. pombe cdc11p, together with sid4p, provides an anchor for septation initiation network proteins on the spindle pole body , 2001, Current Biology.

[25]  S. Moreno,et al.  Flp1, a fission yeast orthologue of the s. cerevisiae CDC14 gene, is not required for cyclin degradation or rum1p stabilisation at the end of mitosis. , 2001, Journal of cell science.

[26]  M. Tyers,et al.  Fission yeast Clp1p phosphatase regulates G2/M transition and coordination of cytokinesis with cell cycle progression , 2001, Current Biology.

[27]  K. Gould,et al.  Vectors and gene targeting modules for tandem affinity purification in Schizosaccharomyces pombe , 2001, Yeast.

[28]  V. Doye,et al.  A Mechanism for Nuclear Positioning in Fission Yeast Based on Microtubule Pushing , 2001, The Journal of cell biology.

[29]  K. Gould,et al.  Timing is everything: regulation of mitotic exit and cytokinesis by the MEN and SIN. , 2001, Trends in cell biology.

[30]  T. Stearns,et al.  gamma-Tubulin. , 2020, Current biology : CB.

[31]  T. J. Keating,et al.  The Role of Xgrip210 in γ-Tubulin Ring Complex Assembly and Centrosome Recruitment , 2000, The Journal of cell biology.

[32]  T. Toda,et al.  The fission yeast γ‐tubulin complex is required in G1 phase and is a component of the spindle assembly checkpoint , 2000 .

[33]  R. Cross,et al.  Dynamics of interphase microtubules in Schizosaccharomyces pombe , 2000, Current Biology.

[34]  E. Nogales,et al.  A mutation in gamma-tubulin alters microtubule dynamics and organization and is synthetically lethal with the kinesin-like protein pkl1p. , 2000, Molecular biology of the cell.

[35]  H. Wang,et al.  A checkpoint that monitors cytokinesis in Schizosaccharomyces pombe. , 2000, Journal of cell science.

[36]  Y. Hiraoka,et al.  Large‐scale screening of intracellular protein localization in living fission yeast cells by the use of a GFP‐fusion genomic DNA library , 2000, Genes to cells : devoted to molecular & cellular mechanisms.

[37]  T. Toda,et al.  The fission yeast gamma-tubulin complex is required in G(1) phase and is a component of the spindle assembly checkpoint. , 2000, The EMBO journal.

[38]  Y. Zheng,et al.  gamma-Tubulin complexes and their role in microtubule nucleation. , 2000, Current topics in developmental biology.

[39]  I. Hagan,et al.  The microtubule organizing centers of Schizosaccharomyces pombe. , 2000, Current topics in developmental biology.

[40]  H. Wang,et al.  Drc1p/Cps1p, a 1,3-beta-glucan synthase subunit, is essential for division septum assembly in Schizosaccharomyces pombe. , 1999, Genetics.

[41]  K. Gould,et al.  Myb-Related Fission Yeast cdc5p Is a Component of a 40S snRNP-Containing Complex and Is Essential for Pre-mRNA Splicing , 1999, Molecular and Cellular Biology.

[42]  A. Woollard,et al.  Analysis of the cps1 gene provides evidence for a septation checkpoint in Schizosaccharomyces pombe , 1999, Molecular and General Genetics MGG.

[43]  V. Simanis,et al.  Controlling septation in fission yeast: finding the middle, and timing it right , 1999, Current Genetics.

[44]  Timothy J. Mitchison,et al.  Characterization of Two Related Drosophila γ-tubulin Complexes that Differ in Their Ability to Nucleate Microtubules , 1999, The Journal of cell biology.

[45]  P. Philippsen,et al.  Heterologous modules for efficient and versatile PCR‐based gene targeting in Schizosaccharomyces pombe , 1998, Yeast.

[46]  I. Hagan,et al.  The fission yeast microtubule cytoskeleton. , 1998, Journal of cell science.

[47]  M. Knop,et al.  The spindle pole body component Spc97p interacts with the γ‐tubulin of Saccharomyces cerevisiae and functions in microtubule organization and spindle pole body duplication , 1997, The EMBO journal.

[48]  K. Gould,et al.  Cytokinesis in fission yeast Schizosaccharomyces pombe. , 1997, Methods in enzymology.

[49]  J. Kilmartin,et al.  The spindle pole body component Spc98p interacts with the gamma‐tubulin‐like Tub4p of Saccharomyces cerevisiae at the sites of microtubule attachment. , 1996, The EMBO journal.

[50]  H. Lieberman.  Extragenic suppressors of Schizosaccharomyces pombe rad9 mutations uncouple radioresistance and hydroxyurea sensitivity from cell cycle checkpoint control. , 1995, Genetics.

[51]  K. Maundrell.  Thiamine-repressible expression vectors pREP and pRIP for fission yeast. , 1993, Gene.

[52]  K. Maundrell,et al.  TATA box mutations in the Schizosaccharomyces pombe nmt1 promoter affect transcription efficiency but not the transcription start point or thiamine repressibility. , 1993, Gene.

[53]  J. Raff,et al.  The centrosome. , 1993, Scientific American.

[54]  H. Prentice,et al.  High efficiency transformation of Schizosaccharomyces pombe by electroporation. , 1992, Nucleic acids research.

[55]  K. Gould,et al.  Phosphorylation at Thr167 is required for Schizosaccharomyces pombe p34cdc2 function. , 1991, The EMBO journal.

[56]  M. Yanagida,et al.  The fission yeast gamma-tubulin is essential for mitosis and is localized at microtubule organizing centers. , 1991, Journal of cell science.

[57]  Yixian Zheng,et al.  γ-Tubulin is present in Drosophila melanogaster and homo sapiens and is associated with the centrosome , 1991, Cell.

[58]  S. Moreno,et al.  Molecular genetic analysis of fission yeast Schizosaccharomyces pombe. , 1991, Methods in enzymology.