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

Srinivas Venkatram; Jennifer L Jennings; Andrew Link; Kathleen L Gould

doi:10.1091/mbc.e04-12-1043

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

Mol Biol Cell. 2005 Jun;16(6):3052-63. doi: 10.1091/mbc.e04-12-1043. Epub 2005 Mar 30.

Authors

Srinivas Venkatram¹, Jennifer L Jennings, Andrew Link, Kathleen L Gould

Affiliation

¹ Department of Cell and Developmental Biology and Howard Hughes Medical Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.

Abstract

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Actins / metabolism*
Anaphase
Antibodies, Monoclonal / metabolism
Bridged Bicyclo Compounds, Heterocyclic / pharmacology
Cell Cycle Proteins / metabolism
Fluorescent Antibody Technique, Indirect
Fluorescent Dyes
Fungal Proteins / genetics*
Fungal Proteins / isolation & purification
Fungal Proteins / metabolism*
GTP-Binding Proteins / metabolism
Gene Deletion
Green Fluorescent Proteins / metabolism
Indoles
Microscopy, Fluorescence
Microscopy, Video
Microtubule-Associated Proteins / genetics
Microtubule-Associated Proteins / metabolism
Microtubule-Organizing Center / metabolism
Microtubules / metabolism*
Recombinant Fusion Proteins / isolation & purification
Recombinant Fusion Proteins / metabolism
Schizosaccharomyces / genetics
Schizosaccharomyces / growth & development
Schizosaccharomyces / metabolism
Schizosaccharomyces pombe Proteins / genetics
Schizosaccharomyces pombe Proteins / metabolism
Spindle Apparatus / metabolism
Thiazoles / pharmacology
Thiazolidines
Tubulin / metabolism

Substances

Actins
Antibodies, Monoclonal
Bridged Bicyclo Compounds, Heterocyclic
CDC15 protein
Cell Cycle Proteins
Fluorescent Dyes
Fungal Proteins
Indoles
Microtubule-Associated Proteins
Recombinant Fusion Proteins
Schizosaccharomyces pombe Proteins
Thiazoles
Thiazolidines
Tubulin
mto2p protein, S pombe
Green Fluorescent Proteins
DAPI
GTP-Binding Proteins
latrunculin A