title: Ras recruits mitotic exit regulator Lte1 to the bud cortex in budding yeast.
abstract: ACdc25 family protein Lte1 (low temperature essential) is essential for mitotic exit at a lowered temperature and has been presumed to be a guanine nucleotide exchange factor (GEF) for a small GTPase Tem1, which is a key regulator of mitotic exit. We found that Lte1 physically associates with Ras2-GTP both in vivo and in vitro and that the Cdc25 homology domain (CHD) of Lte1 is essential for the interaction with Ras2. Furthermore, we found that the proper localization of Lte1 to the bud cortex is dependent on active Ras and that the overexpression of a derivative of Lte1 without the CHD suppresses defects in mitotic exit of a Deltalte1 mutant and a Deltaras1 Deltaras2 mutant. These results suggest that Lte1 is a downstream effector protein of Ras in mitotic exit and that the Ras GEF domain of Lte1 is not essential for mitotic exit but required for its localization.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Ryuji
authors.initials: R
authors.lastname: Ichihashi
authors.forename: Akio
authors.initials: A
authors.lastname: Toh-e
mesh_terms: D002478:Cells, Cultured; D005057:Eukaryotic Cells / Q000378:metabolism*; D005656:Fungal Proteins; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D020662:Guanine Nucleotide Exchange Factors; C089357:LTE1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C095212:CLA4 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases; C489015:RAS2 protein, S cerevisiae; D020846:cdc42 GTP-Binding Protein, Saccharomyces cerevisiae; D018631:ras Proteins