A cytokinesis checkpoint requiring the yeast homologue of an APC-binding protein.
Checkpoint controls ensure that events of the cell-division cycle are completed with fidelity and in the correct order. In budding yeast with a mutation in the motor protein dynein, the mitotic spindle is often misaligned and therefore slow to enter the neck between mother cell and budding daughter cell. When this occurs, cytokinesis (division of the cytoplasm into two) is delayed until the spindle is properly positioned. Here we describe mutations that abolish this delay, indicating the existence of a new checkpoint mechanism. One mutation lies in the gene encoding the yeast homologue of EB1, a human protein that binds the adenomatous polyposis coli (APC) protein, a tumour suppressor. EB1 is located on microtubules of the mitotic spindle and is important in spindle assembly. EB1 may therefore, by associating with microtubules, contribute to the sensor mechanism that activates the checkpoint. Another mutation affects Stt4, a phosphatidylinositol-4-OH kinase. Cold temperature is an environmental stimulus that causes misalignment of the mitotic spindle in yeast and appears to activate this checkpoint mechanism.
Muhua
L
L
Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA.
Adames
N R
NR
Murphy
M D
MD
Shields
C R
CR
Cooper
J A
JA
D019870:1-Phosphatidylinositol 4-Kinase / Q000378:metabolism; D025601:Adenomatous Polyposis Coli Protein; D002455:Cell Division / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000378:metabolism / Q000502:physiology*; D005656:Fungal Proteins / Q000378:metabolism / Q000502:physiology*; D005800:Genes, Fungal; D018816:Genes, cdc; D008869:Microtubule-Associated Proteins / Q000502:physiology*; D008870:Microtubules / Q000502:physiology; D009154:Mutation; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D008941:Spindle Apparatus / Q000502:physiology; D013696:Temperature; D014743:Videotape Recording
D025601:Adenomatous Polyposis Coli Protein; D003598:Cytoskeletal Proteins; C405804:EB1 microtubule binding proteins; D005656:Fungal Proteins; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; D019870:1-Phosphatidylinositol 4-Kinase; C441760:PIK1 protein, S cerevisiae; C112465:STT4 protein, S cerevisiae