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Cex 1 p Facilitates Rna 1 p ‐Mediated Dissociation of the Los 1 p ‐ tRNA ‐ Gsp 1 p ‐ GTP Export Complex
Author(s) -
McGuire Andrew T.,
Mangroo Dev
Publication year - 2012
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2011.01304.x
Subject(s) - gtp' , ran , biology , nuclear export signal , gtpase , rna , microbiology and biotechnology , cytoplasm , transfer rna , biochemistry , cell nucleus , gene , enzyme
Nuclear tRNA export plays an essential role in key cellular processes such as regulation of protein synthesis, cell cycle progression, response to nutrient availability and DNA damage and development. Like other nuclear export processes, assembly of the nuclear tRNA export complex in the nucleus is dependent on Ran ‐ GTP / Gsp 1 p ‐ GTP , and dissociation of the export receptor‐ tRNA ‐ Ran ‐ GTP / Gsp 1 p ‐ GTP complex in the cytoplasm requires RanBP 1/ Yrb 1 p and RanGAP / Rna 1 p to activate the GTPase activity of Ran ‐ GTP / Gsp 1 p ‐ GTP . The S accharomyces cerevisiae Cex 1 p and Human Scyl 1 have also been proposed to participate in unloading of the tRNA export receptors at the cytoplasmic face of the nuclear pore complex ( NPC ). Here, we provide evidence suggesting that Cex 1 p is required for activation of the GTPase activity of Gsp 1 p and dissociation of the receptor‐ tRNA ‐ Gsp 1 p export complex in S . cerevisiae . The data suggest that Cex 1 p recruits Rna 1 p from the cytoplasm to the NPC and facilitates Rna 1 p activation of the GTPase activity of Gsp 1 p by enabling Rna 1 p to gain access to Gsp 1 p ‐ GTP bound to the export receptor tRNA complex. It is possible that this tRNA unloading mechanism is conserved in evolutionarily diverse organisms and that other Gsp 1 p ‐ GTP ‐dependent export processes use a pathway‐specific component to recruit Rna 1 p to the NPC .