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.
Venkatram
Srinivas
S
Department of Cell and Developmental Biology and Howard Hughes Medical Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
Jennings
Jennifer L
JL
Link
Andrew
A
Gould
Kathleen L
KL
D000199:Actins / Q000378:metabolism*; D000705:Anaphase; D000911:Antibodies, Monoclonal / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D005456:Fluorescent Dyes; D005656:Fungal Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D017353:Gene Deletion; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007211:Indoles; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D022101:Microtubule-Organizing Center / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines; D014404:Tubulin / Q000378:metabolism
D000199:Actins; D000911:Antibodies, Monoclonal; D019086:Bridged Bicyclo Compounds, Heterocyclic; C082279:CDC15 protein; D018797:Cell Cycle Proteins; D005456:Fluorescent Dyes; D005656:Fungal Proteins; D007211:Indoles; D008869:Microtubule-Associated Proteins; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D013844:Thiazoles; D053778:Thiazolidines; D014404:Tubulin; C505279:mto2p protein, S pombe; D049452:Green Fluorescent Proteins; C007293:DAPI; D019204:GTP-Binding Proteins; C037067:latrunculin A