TY - JOUR
T1 - RagA is a functional homologue of S. cerevisiae Gtr1p involved in the Ran/Gsp1-GTPase pathway
AU - Hirose, Eiji
AU - Nakashima, Nobutaka
AU - Sekiguchi, Takeshi
AU - Nishimoto, Takeharu
PY - 1998
Y1 - 1998
N2 - Human RagA and RagB is reported to be 52% identical to a putative GTPase of Saccharomyces cerevisiae, Gtr1p. According to the reported nucleotide sequence, we amplified human RagA and RagB(s) cDNAs from the human B cell cDNA library with PCR. Both cDNAs rescued a cold sensitivity of S. cerevisiae, gtr1-11. Furthermore, we introduced into the cloned human RagA cDNA, the mutation 'T21L' corresponding to the gtr1-11 mutation which has been reported to suppress not only all of rcc1-, temperature-sensitive mutants of Ran/Gsp1p GTPase GDP/GTP-exchanging factor, but also rna1-1, a temperature-sensitive mutant of Ran/Gsp1p GTPase-protein. The resulting RagA(gtr1-11) cDNA but significantly, suppressed both rcc1- and rna1-1 mutations. These results indicated that RagA and RagB(s) are functional homologues of S. cervisiae Gtr1p. Interestingly, while wild-type human RagA and RagB(s) were localized within the cytoplasm, similar to S. cerevisiae Gtr1p, the mutated human RagA(gtr1-11) corresponding to a dominant negative form of RagA was distributed in discrete speckles in the nucleus, being localized side by side with SC-35, a non-snRNP of the splicing complex. In contrast, a dominant positive form of RagA, Q66L was localized in the cytoplasm. Thus, RagA was suggested to shuttle between the cytoplasm and the nucleus, depending on the bound nucleotide state.
AB - Human RagA and RagB is reported to be 52% identical to a putative GTPase of Saccharomyces cerevisiae, Gtr1p. According to the reported nucleotide sequence, we amplified human RagA and RagB(s) cDNAs from the human B cell cDNA library with PCR. Both cDNAs rescued a cold sensitivity of S. cerevisiae, gtr1-11. Furthermore, we introduced into the cloned human RagA cDNA, the mutation 'T21L' corresponding to the gtr1-11 mutation which has been reported to suppress not only all of rcc1-, temperature-sensitive mutants of Ran/Gsp1p GTPase GDP/GTP-exchanging factor, but also rna1-1, a temperature-sensitive mutant of Ran/Gsp1p GTPase-protein. The resulting RagA(gtr1-11) cDNA but significantly, suppressed both rcc1- and rna1-1 mutations. These results indicated that RagA and RagB(s) are functional homologues of S. cervisiae Gtr1p. Interestingly, while wild-type human RagA and RagB(s) were localized within the cytoplasm, similar to S. cerevisiae Gtr1p, the mutated human RagA(gtr1-11) corresponding to a dominant negative form of RagA was distributed in discrete speckles in the nucleus, being localized side by side with SC-35, a non-snRNP of the splicing complex. In contrast, a dominant positive form of RagA, Q66L was localized in the cytoplasm. Thus, RagA was suggested to shuttle between the cytoplasm and the nucleus, depending on the bound nucleotide state.
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M3 - Article
C2 - 9394008
AN - SCOPUS:0031985372
VL - 111
SP - 11
EP - 21
JO - Journal of Cell Science
JF - Journal of Cell Science
SN - 0021-9533
IS - 1
ER -