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Yeast Cdk1 translocates to the plus end of cytoplasmic microtubules to regulate bud cortex interactions
Author(s) -
Maekawa Hiromi,
Usui Takeo,
Knop Michael,
Schiebel Elmar
Publication year - 2003
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/cdg063
Subject(s) - library science , medicine , sociology , computer science
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.