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    A nuclear role for the DEAD-box protein Dbp5 in tRNA export
    eLife (2019)
    Azra LariArvind Arul Nambi RajanRima SandhuTaylor ReiterRachel Montpetit
    Dbp5 is an essential DEAD-box protein that mediates nuclear mRNP export. Dbp5 also shuttles between nuclear and cytoplasmic compartments with reported roles in transcription, ribosomal subunit export, and translation; however, the mechanism(s) by which nucleocytoplasmic transport occurs and how Dbp5 specifically contributes to each of these processes remains unclear. Towards understanding the functions and transport of Dbp5 in Saccharomyces cerevisiae, alanine scanning mutagenesis was used to generate point mutants at all possible residues within a GFP-Dbp5 reporter. Characterization of the 456 viable mutants led to the identification of an N-terminal Xpo1-dependent nuclear export signal in Dbp5, in addition to other separation-of-function alleles, which together provide evidence that Dbp5 nuclear shuttling is not essential for mRNP export. Rather, disruptions in Dbp5 nucleocytoplasmic transport result in tRNA export defects, including changes in tRNA shuttling dynamics during recovery from nutrient stress.
    Nuclear export signal
    DEAD box
    Citations (20)
    ROLES OF IMPORTIN IN NUCLEOCYTOPLASMIC TRANSPORT
    Biochemical Society Transactions (1996)
    Dirk GörlichElisa IzaurraldeIain W. Mattaj
    Importin
    Citations (0)
    Nucleocytoplasmic Transport of mRNA
    Elsevier eBooks (1981)
    Thomas E. WebbDorothy E. SchummThomas Palayoor
    Citations (14)
    Structural Views of the Ran GTPase Cycle
    Springer eBooks (2001)
    Klaus ScheffzekAlfred Wittinghofer
    Ran
    Importin
    Nuclear pore
    Nucleoporin
    Citations (0)
    Myb-binding protein 1a is a nucleocytoplasmic shuttling protein that utilizes CRM1-dependent and independent nuclear export pathways
    Experimental Cell Research (2003)
    R Keough
    Nuclear export signal
    Importin
    MYB
    Citations (27)
    The catalytic subunit of DNA polymerase δ is a nucleocytoplasmic shuttling protein
    Experimental Cell Research (2019)
    Yuehong ShenKexin WangRobert Z. Qi
    Nucleoporin
    Nuclear export signal
    Ran
    Citations (6)
    Early Recruitment of AU-Rich Element-Containing mRNAs Determines Their Cytosolic Fate during Iron Deficiency
    Molecular and Cellular Biology (2010)
    Sandra VergaraSergi PuigDennis J. Thiele
    The yeast Cth2 protein is a CX8CX5CX3H tandem zinc finger protein that binds AU-rich element (ARE)-containing transcripts to enhance their decay in response to iron (Fe) deficiency. Mammalian members of this family of proteins are known to undergo nucleocytoplasmic shuttling, but little is known about the role of shuttling in the mechanism of ARE-dependent mRNA decay. Here we demonstrate that, like its mammalian homologues, Cth2 is a nucleocytoplasmic shuttling protein whose nuclear export depends on mRNA transport to the cytosol. The nuclear import information of Cth2 is contained within its tandem zinc finger domain, but it is independent of mRNA-binding function. Moreover, we also demonstrate that nucleocytoplasmic shuttling of Cth2 requires active transcription and that disruption of shuttling leads to defects in Cth2 function in mRNA decay under Fe deficiency. Taken together, our data suggest that under conditions of Fe deficiency Cth2 travels into the nucleus to recruit target mRNAs, perhaps cotranscriptionally, that are destined for cytosolic degradation as part of the mechanism of adaptation to growth under Fe limitation. These data also suggest an important role for nucleocytoplasmic shuttling in this conserved family of proteins in the mechanism of ARE-mediated mRNA decay.
    Nuclear export signal
    Transcription
    Citations (37)
    RNA-Regulated Interaction of Transportin-1 and Exportin-5 with the Double-Stranded RNA-Binding Domain Regulates Nucleocytoplasmic Shuttling of ADAR1
    Molecular and Cellular Biology (2009)
    Jutta FritzAlexander StrehblowAndreas TaschnerSandy SchopoffPaweł Pasierbek
    Double-stranded RNA (dsRNA)-binding proteins interact with substrate RNAs via dsRNA-binding domains (dsRBDs). Several proteins harboring these domains exhibit nucleocytoplasmic shuttling and possibly remain associated with their substrate RNAs bound in the nucleus during nuclear export. In the human RNA-editing enzyme ADAR1-c, the nuclear localization signal overlaps the third dsRBD, while the corresponding import factor is unknown. The protein also lacks a clear nuclear export signal but shuttles between the nucleus and the cytoplasm. Here we identify transportin-1 as the import receptor for ADAR1. Interestingly, dsRNA binding interferes with transportin-1 binding. At the same time, each of the dsRBDs in ADAR1 interacts with the export factor exportin-5. RNA binding stimulates this interaction but is not a prerequisite. Thus, our data demonstrate a role for some dsRBDs as RNA-sensitive nucleocytoplasmic transport signals. dsRBD3 in ADAR1 can mediate nuclear import, while interaction of all dsRBDs might control nuclear export. This finding may have implications for other proteins containing dsRBDs and suggests a selective nuclear export mechanism for substrates interacting with these proteins.
    Nuclear export signal
    RNA Silencing
    Citations (120)
    Translin: Localization and evidence for regulated nucleocytoplasmic shuttling
    Jennifer Lee Phillips
    Citations (0)
    KETCHing up with Gametogenesis: Nucleocytoplasmic Import and Cell Cycle
    The Plant Cell (2020)
    Sébastien Andreuzza
    In eukaryotes, active import of large signaling molecules and proteins over 40 kD in the nucleus is mediated by aptly named “importin” proteins. As there are considerably fewer importins than there are cargos, determining how cargo-transporter specificity is mediated constitutes a challenging
    Importin
    Karyopherin
    Ran
    Citations (0)