A Distinct and Parallel Pathway for the Nuclear Import of an mRNA-binding Protein

Pemberton, Lucy F.; Rosenblum, Jonathan S.; Blobel, Günter

doi:10.1083/jcb.139.7.1645

Cited by 97 publications

(116 citation statements)

References 63 publications

(130 reference statements)

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“…Consistent with this model, mtr10D los1D cells have a tRNA splicing defect similar to los1D cells (Murthi et al 2010). As Mtr10 has been shown to import proteins such as Npl3 into the nucleus (Pemberton et al 1997) and lacks obvious RNA binding motifs, Mtr10 may import tRNA into the nucleus via an adapter protein. Retrograde transport of tRNA provides a mechanism by which spliced tRNA accumulates in nuclei.…”

Section: Introductionsupporting

confidence: 58%

P-body components, Dhh1 and Pat1, are involved in tRNA nuclear-cytoplasmic dynamics

Hurto¹,

Hopper²

2011

RNA

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The nuclear-cytoplasmic distribution of tRNA depends on the balance between tRNA nuclear export/re-export and retrograde tRNA nuclear import in Saccharomyces cerevisiae. The distribution of tRNA is sensitive to nutrient availability as cells deprived of various nutrients exhibit tRNA nuclear accumulation. Starvation induces numerous events that result in translational repression and P-body formation. This study investigated the possible coordination of these responses with tRNA nuclearcytoplasmic distribution. Dhh1 and Pat1 function in parallel to promote translation repression and P-body formation in response to starvation. Loss of both, Dhh1 and Pat1, results in a failure to repress translation and to induce P-body formation in response to glucose starvation. This study reports that nutrient deprived dhh1 pat1 cells also fail to accumulate tRNA within nuclei. Conversely, inhibition of translation initiation and induction of P-body formation by overproduction of Dhh1 or Pat1 cause tRNA nuclear accumulation in nutrient-replete conditions. Also, loss of the mRNA decapping activator, Lsm1, causes tRNA nuclear accumulation. However, the coordination between P-body formation, translation repression, and tRNA distribution is limited to the early part of the P-body formation/translation repression pathway as loss of mRNA decapping or 59 to 39 degradation does not influence tRNA nuclear-cytoplasmic dynamics. The data provide the first link between P-body formation/translation initiation and tRNA nuclear-cytoplasmic dynamics. The current model is that Dhh1 and Pat1 function in parallel to promote starvation-induced tRNA nuclear accumulation.

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Section: Introductionsupporting

confidence: 58%

P-body components, Dhh1 and Pat1, are involved in tRNA nuclear-cytoplasmic dynamics

Hurto¹,

Hopper²

2011

RNA

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“…Kap114-PrA or Sua7-TAP and their associated proteins were isolated using IgG-Sepharose as described (Aitchison et al, 1996;Pemberton et al, 1997). Western blotting was performed by transferring the proteins onto polyvinylidene difluoride membrane and probing with antibodies as noted.…”

Section: Cytosol Preparation and Western Blottingmentioning

confidence: 99%

“…For each figure, the GFP images were acquired using identical exposure settings and manipulated identically using Adobe Photoshop (San Jose, CA). After fixation in 3.7% formaldehyde for 20 min, immunofluorescence microscopy on yeast spheroplasts was performed as previously described (Pemberton et al, 1997). Anti-Sua7 rabbit polyclonal antibodies were used to detect Sua7p (Liu et al, 2001; a gift from David Auble, University of Virginia), followed by Cy3-conjugated donkey anti-rabbit IgG (Jackson Laboratories, ImmunoResearch Laboratories, West Grove, PA).…”

Section: Cell Culture and Microscopymentioning

confidence: 99%

Nuclear Import of TFIIB Is Mediated by Kap114p, a Karyopherin with Multiple Cargo-binding Domains

Hodges

Leslie

Mosammaparast

et al. 2005

MBoC

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Nuclear import and export is mediated by an evolutionarily conserved family of soluble transport factors, the karyopherins (referred to as importins and exportins). The yeast karyopherin Kap114p has previously been shown to import histones H2A and H2B, Nap1p, and a component of the preinitiation complex (PIC), TBP. Using a proteomic approach, we have identified several potentially new cargoes for Kap114p. These cargoes include another PIC component, the general transcription factor IIB or Sua7p, which interacted directly with Kap114p. Consistent with its role as a Sua7p import factor, deletion of KAP114 led to specific mislocalization of Sua7p to the cytoplasm. An interaction between Sua7p and TBP was also detected in cytosol, raising the possibility that both Sua7p and TBP can be coimported by Kap114p. We have also shown that Kap114p possesses multiple overlapping binding sites for its partners, Sua7p, Nap1p, and H2A and H2B, as well as RanGTP and nucleoporins. In addition, we have assembled an in vitro complex containing Sua7p, Nap1p, and histones H2A and H2B, suggesting that this Kap may import several proteins simultaneously. The import of more than one cargo at a time would increase the efficiency of each import cycle and may allow the regulation of coimported cargoes. INTRODUCTIONIn eukaryotic cells the nucleocytoplasmic transport of most proteins and some RNAs is mediated by an evolutionarily conserved family of soluble transport factors, the karyopherins (also referred to as importins and exportins; reviewed in Weis, 2003;Harel and Forbes, 2004;Mosammaparast and Pemberton, 2004). After synthesis in the cytoplasm, most nuclear protein cargoes are bound by a member of the karyopherin family, through direct interaction with a nuclear localization sequence contained in the cargo protein. Transport through the nuclear pore complex occurs via transient interactions of the karyopherin with the NPC. Once in the nucleus, the karyopherin encounters a high concentration of RanGTP, which acts as a regulator of transport. Interaction of the karyopherin with RanGTP leads to dissociation of the karyopherin from its nuclear cargo (Weis, 2003;Harel and Forbes, 2004;Mosammaparast and Pemberton, 2004). In some circumstances, nuclear-binding partners of the cargo appear to also play a role in stimulating the dissociation of Kap and cargo (Senger et al., 1998;Lee and Aitchison, 1999;Pemberton et al., 1999). In yeast, there are 14 members of the karyopherin family, with Ͼ20 members in mammalian cells (Mosammaparast and Pemberton, 2004). Karyopherins appear to function in either nuclear import or nuclear export, with only two examples of a Kap that works in both directions (Weis, 2003;Harel and Forbes, 2004;Mosammaparast and Pemberton, 2004). In yeast, 11 members of the karyopherin family must import at least 1500 nuclear proteins, suggesting that each receptor must have many cargoes. To date specific transport receptor-cargo pairs have only been shown for ϳ30 cargoes; in addition the NLS sequences recognized by most Kaps is n...

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“…3Q-T) was unaffected by the csel-I mutation as compared to the wildtype situation. This control was chosen since Npl3p shuttles continuously, like Srplp, between nucleus and cytoplasm [63], but exploits a different importin for its nuclear import, Mtrl0p [24,25]. For recognition by Mtrl0p the C-terminal 130 amino acids (residues 284414) were shown to be necessary and sufficient [25].…”

Section: Gfp-npl3nls Nomarskimentioning

confidence: 99%

“…Characterized nuclear import and export receptors include, besides importin 13 (karyopherin [31) and its yeast homolog Kap95p [14][15][16][17][18], transportin (karyopherin [32) and yeast Kapl04p [19,20]), the import receptor for some hnRNP proteins, karyopherin [33 (yeast Pselp/Kapl21p) and [34 (yeast Yrb4p/Kap123p) [21][22][23], conferring nuclear import of ribosomal proteins, Mtrl0p [24,25], the nuclear import receptor for the yeast hnRNP protein Npl3p, Sxmlp [26], mediating nuclear import of the yeast La homolog, CRM1 (yeast Xpolp) [27][28][29][30], the export receptor for proteins containing a leucine-rich nuclear export signal (NES), and hLOS1 and yeast Loslp [31][32][33]), an export receptor for tRNA (for more references see [4,5]). …”

Section: Introductionmentioning

confidence: 99%

Cselp functions as the nuclear export receptor for importin α in yeast

Künzler

Hurt

1998

FEBS Letters

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CSEI is essential for yeast cell viability and has been implicated in chromosome segregation. Based on its sequence similarity, Cselp has been grouped into the family of importin like nucleocytoplasmic transport receptors with highest homology to the recently identified human nuclear export receptor for importin ~, CAS. We demonstrate here that Cselp physically interacts with yeast Ran and yeast importin tx (Srplp) in the yeast two-hybrid system and that recombinant Cselp, Srplp and Ran-GTP form a trimeric complex in vitro. Re-export of Srplp from the nucleus into the cytoplasm and nuclear uptake of a reporter protein containing a classical NLS are inhibited in a csel mutant strain. These findings suggest that Cselp is the exportin of importin ¢z in yeast.

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A Distinct and Parallel Pathway for the Nuclear Import of an mRNA-binding Protein

Cited by 97 publications

References 63 publications

P-body components, Dhh1 and Pat1, are involved in tRNA nuclear-cytoplasmic dynamics

P-body components, Dhh1 and Pat1, are involved in tRNA nuclear-cytoplasmic dynamics

Nuclear Import of TFIIB Is Mediated by Kap114p, a Karyopherin with Multiple Cargo-binding Domains

Cselp functions as the nuclear export receptor for importin α in yeast

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