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The nuclear GTPase Gsp1p can affect proper telomeric function through the Sir4 protein in Saccharomyces cerevisiae
Author(s) -
Clément Martin,
Deshaies Francis,
de Repentigny Louis,
Belhumeur Pierre
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05374.x
Subject(s) - saccharomyces cerevisiae , biology , ran , nuclear transport , nuclear pore , microbiology and biotechnology , nucleoporin , nuclear protein , nuclear export signal , gene silencing , gtpase , function (biology) , small gtpase , telomere , genetics , cell nucleus , yeast , cytoplasm , signal transduction , gene , transcription factor
Summary The small Ras‐like GTPase Ran/Gsp1p is a highly conserved nuclear protein required for the nucleocytoplasmic trafficking of macromolecules. Recent findings suggest that the Ran/Gsp1p pathway may have additional roles in several aspects of nuclear structure and function, including spindle assembly, nuclear envelope formation, nuclear pore complex assembly and RNA processing. Here, we provide evidence that Gsp1p can regulate telomeric function in Saccharomyces cerevisiae . We show that overexpression of PRP20 , encoding the Gsp1p GDP/GTP nuclear exchange factor, specifically weakens telomeric silencing without detectably affecting nucleocytoplasmic transport. In addition to this silencing defect, we show that Rap1p and Sir3p delocalize from their normal telomeric foci. Interestingly, Gsp1p was found to interact genetically and physically with the telomeric component Sir4p. Taken together, these results suggest that the GSP1 pathway could regulate proper telomeric function in yeast through Sir4p.