|
||
© The Rockefeller University Press,
0021-9525/2000//1115 $5.00
The Journal of Cell Biology, Volume 148, Number 6,
, 2000 1115-1122
Brief Report |
Nucleocytoplasmic Shuttling of the Cdc42p Exchange Factor Cdc24p
ra2{at}mrc-lmb.cam.ac.uk
Cdc24p, the GDP/GTP exchange factor for the regulator of actin cytoskeleton Cdc42p, localizes to sites of polarized growth. Here we show that Cdc24p shuttles in and out of the yeast nucleus during vegetative growth. Far1p is necessary and sufficient for nuclear accumulation of Cdc24p, suggesting that its nuclear import occurs via an association with Far1p. Nuclear export is triggered either by entry into the cell cycle or by mating pheromone. As Far1p is degraded upon entry into the cell cycle, cell cycle–dependent export of Cdc24p occurs in the absence of Far1p, whereas during mating similar export kinetics indicate that a Cdc24p–Far1p complex is exported. Our results suggest that the nucleus serves as a store of preformed Cdc24p–Far1p complex which is required for chemotropism.
Key Words: nucleocytoplasmic shuttling GDP/GTP exchange factor Far1p Cdc24p polarized growth
© 2000 The Rockefeller University Press
|
|