Nuclear Import of the TATA-binding Protein: Mediation by the Karyopherin Kap114p and a Possible Mechanism for Intranuclear Targeting

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

doi:10.1083/jcb.145.7.1407

Cited by 108 publications

(153 citation statements)

References 62 publications

(143 reference statements)

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“…The localization of GR-GFP was monitored in 14 yeast strains each deficient in a different nuclear transport receptor: CRMI (Stade et al, 1997), CSEI (Xiao et al, 1993), Kap95 (Iovine et al, 1995), Kap104 (Aitchison et al, 1996), Kap123 (Seedorf and Silver, 1997), LOS1 (Hopper et al, 1980), MSN5 (Kaffman et al, 1998a), MTR10 (Kadowaki et al, 1994), NMD5 (He and Jacobson, 1995), PSEI (Seedorf and Silver, 1997), SRP1 (Yano et al, 1992), SXM1 (Seedorf and Silver, 1997), Kap114 (Morehouse et al, 1999;Pemberton et al, 1999), and PDR6 (Titov and Blobel, 1999). Yeast strains PSY580, pse1-1, PSY1200, and PSY902 have been described (Seedorf and Silver, 1997).…”

Section: Yeast Strains Handling Transformations and Localization Smentioning

confidence: 99%

“…Two microliters of this suspension was spotted on a slide beneath a coverslip, and protein localization was assessed by fluorescence microscopy with a 100ϫ oil immersion lens on the Zeis microscope described above. For hormone withdrawal experiments, yeast were washed three times in SD medium lacking hormone and incubated at 30°C for 1 h.The localization of GR-GFP was monitored in 14 yeast strains each deficient in a different nuclear transport receptor: CRMI (Stade et al, 1997), CSEI (Xiao et al, 1993), Kap95 (Iovine et al, 1995), Kap104 (Aitchison et al, 1996), Kap123 (Seedorf and Silver, 1997), LOS1 (Hopper et al, 1980), MSN5 (Kaffman et al, 1998a, MTR10 (Kadowaki et al, 1994), NMD5 (He andJacobson, 1995), PSEI (Seedorf and Silver, 1997), SRP1 (Yano et al, 1992), SXM1 (Seedorf and Silver, 1997), Kap114 (Morehouse et al, 1999;Pemberton et al, 1999), and PDR6 (Titov and. Yeast strains PSY580, pse1-1, PSY1200, and PSY902 have been described (Seedorf and Silver, 1997).…”

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Importin 7 and Importin α/Importin β Are Nuclear Import Receptors for the Glucocorticoid Receptor

Freedman

2004

MBoC

192

151

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The vertebrate glucocorticoid receptor (GR) is cytoplasmic without hormone and localizes to the nucleus after hormone binding. GR has two nuclear localization signals (NLS): NL1 is similar in sequence to the SV40 NLS; NL2 is poorly defined, residing in the ligand-binding domain. We found that GR displayed similar hormone-regulated compartmentalization in Saccharomyces cerevisiae and required the Sxm1 nuclear import receptor for NL2-mediated import. Two metazoan homologues of Sxm1, importin 7 and importin 8, bound both NL1 and NL2, whereas importin ␣ selectively bound NL1. In an in vitro nuclear import assay, both importin 7 and the importin ␣-importin ␤ heterodimer could import a GR NL1 fragment. Under these conditions, full-length GR localized to nuclei in the presence but not absence of an unidentified component in cell extracts. Interestingly, importin 7, importin 8, and importin ␣ bound GR even in the absence of hormone; thus, hormonal control of localization is exerted at a step downstream of import receptor binding. INTRODUCTIONTo survive in a complex environment, cells sense external cues and commonly respond by altering gene expression, in part by regulating the intracellular localization and activity of transcriptional regulatory factors. For example, the intracellular localization of the yeast Pho4 and mammalian SREBP factors is altered in response to changes in external phosphate and circulating sterol concentrations, respectively (Kaffman et al., 1998b;Nagoshi et al., 1999). Similarly, changes in blood glucose levels and a wide range of physiological stress signals modulate the circulating level of glucocorticoids, changing the activity and localization of the glucocorticoid receptor (GR). Within minutes of glucocorticoid binding, GR enters the nucleus and activates or represses target gene transcription (Picard and Yamamoto, 1987). However, hormone binding is reversible; after hormone withdrawal, GR locates back to the cytoplasm (t 1/2 ϭ 10 h; Hache et al., 1999).Proteins and RNAs enter and exit the nucleus through the nuclear pore, a 125-MDa complex in the nuclear envelope (Stoffler et al., 1999). Small molecules readily diffuse through the nuclear pore, whereas molecules greater than ϳ40 kDa require import and export machinery for transport (Davis, 1995;Pante and Aebi, 1995). The first nuclear localization sequence (NLS) was identified in the SV40 large T-antigen (Kalderon et al., 1984). Development of an in vitro nuclear import assay facilitated the identification of two proteins that import substrates containing SV40 NLS-like domains. The adapter molecule importin ␣ binds to the NLS of the substrate and the importin ␤ transport receptor, creating a trimeric complex that imports the substrate into the nucleus through the nuclear pore (Strom and Weis, 2001).Based on similarity to importin ␤, a family of nuclear import and export receptors was identified and shown to transport a wide variety of proteins and RNAs into and out of the nucleus. After reaching the nucleoplasm, import receptors bind the...

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Section: Yeast Strains Handling Transformations and Localization Smentioning

confidence: 99%

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confidence: 99%

Importin 7 and Importin α/Importin β Are Nuclear Import Receptors for the Glucocorticoid Receptor

Freedman

2004

MBoC

192

151

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“…Indeed many essential yeast nuclear proteins appear to have more than one route into the nucleus, with the preferred route being mediated by a nonessential karyopherin (Rout et al, 1997;Pemberton et al, 1999;Mosammaparast et al, 2001Mosammaparast et al, , 2002b It has been previously shown that the TATA-binding protein is imported by the karyopherin Kap114p (Morehouse et al., 1999;Pemberton et al, 1999). However in the absence of Kap114p, other karyopherins appear to be able to take its place (Pemberton et al, 1999). Transcription of genes by RNA polymerase II (RNAP II) involves many steps, some of the earliest being the recruitment of general transcription factors and RNAP II to form the preinitiation complex (PIC; Hampsey, 1998;Hahn, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…To add to the complexity of determining which Kap imports a particular cargo, it has been shown that several proteins can be imported into the nucleus by more than one Kap (Rout et al, 1997;Jakel and Gorlich, 1998;Pemberton et al, 1999;Mosammaparast et al, 2001Mosammaparast et al, , 2002bMuhlhausser et al, 2001). Indeed many essential yeast nuclear proteins appear to have more than one route into the nucleus, with the preferred route being mediated by a nonessential karyopherin (Rout et al, 1997;Pemberton et al, 1999;Mosammaparast et al, 2001Mosammaparast et al, , 2002b It has been previously shown that the TATA-binding protein is imported by the karyopherin Kap114p (Morehouse et al., 1999;Pemberton et al, 1999). However in the absence of Kap114p, other karyopherins appear to be able to take its place (Pemberton et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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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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Nuclear import and export pathways

Moroianu

1999

J. Cell. Biochem.

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Macromolecules enter or leave the nucleus by using nuclear localization signals (NLS), or nuclear export signals (NES), respectively. Different types of NLS and NES are recognized directly or indirectly via adapters, by transport receptors. All transport receptors identified thus far are members of the same family and share an ability to shuttle between the nucleus and the cytoplasm, and to interact with the small GTPase Ran and with nucleoporins at the nuclear pore complex (NPC). The GTPase Ran regulates the interaction of transport receptors with either cargoes, or adapters, or nucleoporins and is crucial in providing directionality to nuclear import and export. Surprisingly, GTP hydrolysis by Ran is not required for translocation of some receptor/cargo complexes through the NPC. One of the challenges for the future will be to establish the mechanisms of translocation through the NPC of different transport receptors together with their cargoes.

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Nuclear Import of the TATA-binding Protein: Mediation by the Karyopherin Kap114p and a Possible Mechanism for Intranuclear Targeting

Cited by 108 publications

References 62 publications

Importin 7 and Importin α/Importin β Are Nuclear Import Receptors for the Glucocorticoid Receptor

Importin 7 and Importin α/Importin β Are Nuclear Import Receptors for the Glucocorticoid Receptor

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

Nuclear import and export pathways

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