Yeast Cdk1 translocates to the plus end of cytoplasmic microtubules to regulate bud cortex interactions.
The budding yeast spindle aligns along the mother- bud axis through interactions between cytoplasmic microtubules (CMs) and the cell cortex. Kar9, in complex with the EB1-related protein Bim1, mediates contacts of CMs with the cortex of the daughter cell, the bud. Here we established a novel series of events that target Kar9 to the bud cortex. First, Kar9 binds to spindle pole bodies (SPBs) in G(1) of the cell cycle. Secondly, in G(1)/S the yeast Cdk1, Cdc28, associates with SPBs and phosphorylates Kar9. Thirdly, Kar9 and Cdc28 then move from the SPB to the plus end of CMs directed towards the bud. This movement is dependent upon the microtubule motor protein Kip2. Cdc28 activity is required to concentrate Kar9 at the plus end of CMs and hence to establish contacts with the bud cortex. The Cdc28-regulated localization of Kar9 is therefore an integral part of the program that aligns spindles.
Maekawa
Hiromi
H
The Paterson Institute for Cancer Research, Christie Hospital NHS Trust, Wilmslow Road, Manchester M20 4BX, UK.
Usui
Takeo
T
Knop
Michael
M
Schiebel
Elmar
E
D016203:CDC2 Protein Kinase / Q000378:metabolism; D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D002453:Cell Cycle / Q000502:physiology; D018797:Cell Cycle Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008868:Microtubule Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D021381:Protein Transport / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism; D020798:Two-Hybrid System Techniques
C119683:BIM1 protein, S cerevisiae; D018797:Cell Cycle Proteins; C110443:KAR9 protein, S cerevisiae; D008868:Microtubule Proteins; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D016203:CDC2 Protein Kinase; D017489:CDC28 Protein Kinase, S cerevisiae