Temperature-sensitive defects of the GSP1gene, yeast Ran homologue, activate the Tel1-dependent pathway.
RanGTPase is involved in many cellular processes. It functions in nuclear-cytosolic transport and centrosome formation. Ran also localizes to chromatin as RCC1 does, its guanine nucleotide exchange factor, but Ran's function on chromatin is not known. We found that gsp1, a temperature-sensitive mutant of GSP1, a Saccharomyces cerevisiae Ran homologue, suppressed the hydroxyurea (HU) and ultra violet (UV) sensitivities of the mec1 mutant. In UV-irradiated mec1 gsp1 cells, Rad53 was phosphorylated despite the lack of Mec1. This suppression depended on the TEL1 gene, given that the triple mutant, mec1 gsp1 tel1, was unable to grow. The gsp1 mutations also suppressed the HU sensitivity of the rad9 mutant in a Tel1-dependent manner, but not the HU sensitivity of the rad53 mutant. These results indicated that Rad53 was activated by the Tel1 pathway in mec1 gsp1 cells, suggesting that Gsp1 helps regulate the role switching the ATM family kinases Mec1 and Tel1.
Hayashi
Naoyuki
N
Department of Molecular Pathology, Cancer Research Institute, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-0934, Japan. naoyuki@kenroku.kanazawa-u.ac.jp
Murakami
Seishi
S
Tsurusaki
Susumu
S
Nagaura
Zen-ichiro
Z
Oki
Masaya
M
Nishitani
Hideo
H
Kobayashi
Masahiko
M
Shimizu
Hiroko
H
Yamamoto
Ken-ichi
K
Nishimoto
Takeharu
T
D049109:Cell Proliferation; D020868:Gene Silencing; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013696:Temperature; D020931:ran GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D017346:Protein Serine-Threonine Kinases; C513623:TEL1 protein, S cerevisiae; D020931:ran GTP-Binding Protein