Lm. Frenz et al., The budding yeast Dbf2 protein kinase localises to the centrosome and moves to the bud neck in late mitosis, J CELL SCI, 113(19), 2000, pp. 3399-3408
Dbf2 is a multifunctional protein kinase in Saccharomyces cerevisiae that f
unctions in transcription, the stress response and as part of a network of
genes in exit from mitosis, By analogy with fission yeast it seemed likely
that these mitotic exit genes would be involved in cytokinesis. As a prelim
inary investigation of this we have used Dbf2 tagged with GFP to examine in
tracellular localisation of the protein in living cells. Dbf2 is found on t
he centrosomes/spindle pole bodies (SPBs) and also at the bud neck where it
forms a double ring. The localisation of Dbf2 is cell cycle regulated. it
is on the SPBs for much of the cell cycle and migrates from there to the bu
d neck in late mitosis, consistent with a role in cytokinesis. Dbf2 partly
co-localises with septins at the bud neck. A temperature-sensitive mutant o
f dbf2 also blocks progression of cytokinesis at 37 degreesC, Following cyt
okinesis some Dbf2 moves into the nascent bud. Localisation to the bud neck
depends upon the septins and also the mitotic exit network proteins Mob1,
Cdc5, Cdc14 and Cdc15, The above data are consistent with Dbf2 acting downs
tream in a pathway controlling cytokinesis.