Far1

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About Far1

Far1 contains a putative MAPK-binding sequence at residues 72-82. Metodiev et al. 2002 PMID 12029138

Far1 is phosphorylated at S87 by Cdc28, and at T306 by Fus3. Gartner et al., 1998 PMID 9632750

Far1 expression is upregulated in response to pheromone treatment. Chang & Herskowitz. 1990 PMID 2147873

Far1 degradation may be regulated by phosphorylation, perhaps by the CLN proteins. McKinney et al. 1993 PMID 8491380
- Phosphorylated Far1 appears just before the rapid decline in Far1 protein abundance at the cell cycle Start.

Far1 is expressed in a cell cycle dependent manner. Oehlen et al. 1996 PMID 8649392

Far1 contains a bipartite nuclear localization sequence at residues 11-30,38-48. These residues are necessary and sufficient for nuclear localization. Blondel et al. 1999 PMID 10485850

Far1 is exported from the nucleus by Msn5 (also known as Ste21, often referred to as Msn5/Ste21). Blondel et al. 1999 PMID 10485850
- When Msn5 is overexpressed, export of Far1 from the nucleus does not require a functioning mating pathway, although pheromone treatment does increase cyctoplasmic localization of Far1.
- Pheromone-treatment doesn't noticeably affect the two-hybrid interaction between Msn5 and Far1, suggesting that pheromone may not regulate the interaction between Far1 and Msn5.
- Cytoplasmic localization of Far1 caused by Msn5 overexpression does not activate the mating pathway.
- The ability of Far1 to bind Msn5 is separable from its ability to bind Cdc28.

Cytoplasmic Far1 appears to be involved in determining cell polarity, and nuclear Far1 is important for cell cycle arrest. Blondel et al. 1999 PMID 10485850

WT Far1 (nuclear) has a half-life of about 20 minutes (averaged over the cell cycle). Blondel et al. 2000 PMID 11080155
- Far1 missing the N-terminal NLS (cytoplasmic) has a half-life of 45-55 minutes.
- Far1(S87A) (nuclear), which cannot be phosphorylated by Cdc28, has a half-life of 60 minutes.
- Far1(S87A) missing the N-terminal NLS (cytoplasmic) has a half-life of 100 minutes, suggesting the mechanism that stabilizes cytoplasmic Far1 and the mechanism that stabilizes non-phosphorylatable Far1 may be different.

Both nuclear and cytoplasmic Far1 can be phosphorylated by Cdc28-Cln. Blondel et al. 2000 PMID 11080155
- Cln1 and Cln2 are localized to both the nucleus and cytoplasm.

Evidence suggests that Far1 is efficiently ubiquitinated and degraded in the nucleus. Blondel et al. 2000 PMID 11080155
- Although Cdc53, Skp1, Cdc43 and Hrt1 are localized to both the nucleus and cytoplasm, Cdc4 is exclusively localized to the nucleus.
- Localization of Cdc4 to the cytoplasm destabilizes cytoplasmic Far1.

Far1(MAPK_site, S87~none~PO4, T306~none~PO4)

Far1(MAPK_site, S87~none, T306~none) Far1_tot_conc