Nuclear import of BCL11B is mediated by a classical nuclear localization signal and not the Krüppel-like zinc fingers

The Krüppel-like transcription factor BCL11B is characterized by wide tissue distribution and crucial functions in key developmental and cellular processes and various pathologies including cancer or HIV infection. Although basics of BCL11B activity and relevant interactions with other proteins were uncovered, how this exclusively nuclear protein localizes to its compartment remained unclear. Here, we demonstrate that unlike other KLFs, BCL11B does not require the C-terminal DNA-binding domain to pass through the nuclear envelope but encodes an independent, previously unidentified nuclear localization signal (NLS) which is located distantly from the zinc finger domains and fulfills the essential criteria of an autonomous NLS. First, it can redirect a heterologous cytoplasmic protein to the nucleus. Second, its mutations cause aberrant localization of the protein of origin. Finally, we provide experimental and in silico evidences of the direct interaction with importin alpha. The relative conservation of this motif allows formulating a consensus sequence (K/R)K-X13-14-KR+K++ which can be found in all BCL11B orthologues among vertebrates and in the closely related protein BCL11A.

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Identification of a Common Subnuclear Localization Signal

Molecular Biology of the Cell ◽

10.1091/mbc.e07-03-0295 ◽

2007 ◽

Vol 18 (10) ◽

pp. 3966-3977 ◽

Cited By ~ 25

Author(s):

Karim Mekhail ◽

Luis Rivero-Lopez ◽

Ahmad Al-Masri ◽

Caroline Brandon ◽

Mireille Khacho ◽

...

Keyword(s):

Nuclear Localization ◽

Nuclear Localization Signal ◽

Dynamic Properties ◽

Consensus Sequence ◽

Molecular Networks ◽

Subnuclear Localization ◽

Transcription Regulator ◽

High Affinity ◽

Localization Signal ◽

Membrane Bound

Proteins share peptidic sequences, such as a nuclear localization signal (NLS), which guide them to particular membrane-bound compartments. Similarities have also been observed within different classes of signals that target proteins to membrane-less subnuclear compartments. Common localization signals affect spatial and temporal subcellular organization and are thought to allow the coordinated response of different molecular networks to a given signaling cue. Here we identify a higher-order and predictive code, {[RR(I/L)X3r](n, n≥1)+[L(φ/N)(V/L)](n,n>1)}, that establishes high-affinity interactions between a group of proteins and the nucleolus in response to a specific signal. This position-independent code is referred to as a nucleolar detention signal regulated by H+ (NoDSH+) and the class of proteins includes the cIAP2 apoptotic regulator, VHL ubiquitylation factor, HSC70 heat shock protein and RNF8 transcription regulator. By identifying a common subnuclear targeting consensus sequence, our work reveals rules governing the dynamics of subnuclear organization and ascribes new modes of regulation to several proteins with diverse steady-state distributions and dynamic properties.

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Characterization of the Nuclear Localization Signal of the Borna Disease Virus Polymerase

Journal of Virology ◽

10.1128/jvi.76.16.8460-8467.2002 ◽

2002 ◽

Vol 76 (16) ◽

pp. 8460-8467 ◽

Cited By ~ 13

Author(s):

Michelle Portlance Walker ◽

W. Ian Lipkin

Keyword(s):

Disease Virus ◽

Nuclear Localization ◽

Nuclear Localization Signal ◽

Rna Virus ◽

Flag Epitope ◽

Borna Disease Virus ◽

Localization Signal ◽

Infected Cells ◽

Pass Through ◽

Borna Disease

ABSTRACT Borna disease virus (BDV) is a nonsegmented negative-strand RNA virus that replicates and transcribes its genome in the nucleus of infected cells. BDV proteins involved in replication and transcription must pass through the nuclear envelope to associate with the genomic viral RNA. The RNA-dependent RNA polymerase (L) of BDV is postulated to be the catalytic enzyme of replication and transcription. We demonstrated previously that BDV L localizes to the nucleus of BDV-infected cells and L-transfected cells. Nuclear localization of the protein presupposes the presence of a nuclear localization signal (NLS) within its primary amino acid sequence or cotransport to the nucleus with another karyophilic protein. Because L localized to the nucleus in the absence of other viral proteins, we investigated the possibility that L contains an NLS. The minimal sequence required for nuclear localization of L was identified by analyzing the subcellular distribution of deletion mutants of L fused to a flag epitope tag or β-galactosidase. Although the majority of the L fusion proteins localized to the cytoplasm of transfected BSR-T7 cells, a strong NLS (844RVVKLRIAP852) with basic and proline residues was identified. Mutation of this sequence resulted in cytoplasmic distribution of L, confirming that this sequence was necessary and sufficient to drive the nuclear localization of L.

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Structural determination of importin alpha in complex with beak and feather disease virus capsid nuclear localization signal

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2013.07.122 ◽

2013 ◽

Vol 438 (4) ◽

pp. 680-685 ◽

Cited By ~ 8

Author(s):

Edward I. Patterson ◽

Andrew K. Dombrovski ◽

Crystall M.D. Swarbrick ◽

Shane R. Raidal ◽

Jade K. Forwood

Keyword(s):

Disease Virus ◽

Nuclear Localization ◽

Nuclear Localization Signal ◽

Structural Determination ◽

Virus Capsid ◽

Importin Alpha ◽

Localization Signal ◽

Feather Disease Virus

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Metal-Responsive Transcription Factor 1 (MTF-1) Activity Is Regulated by a Nonconventional Nuclear Localization Signal and a Metal-Responsive Transactivation Domain

Molecular and Cellular Biology ◽

10.1128/mcb.00847-09 ◽

2009 ◽

Vol 29 (23) ◽

pp. 6283-6293 ◽

Cited By ~ 27

Author(s):

Uschi Lindert ◽

Mirjam Cramer ◽

Michael Meuli ◽

Oleg Georgiev ◽

Walter Schaffner

Keyword(s):

Transcription Factor ◽

Dna Binding ◽

Nuclear Localization ◽

Nuclear Localization Signal ◽

Zinc Fingers ◽

Binding Domain ◽

Dna Binding Domain ◽

Activation Domain ◽

Localization Signal ◽

Transcription Factor 1

ABSTRACT Metal-responsive transcription factor 1 (MTF-1) mediates both basal and heavy metal-induced transcription of metallothionein genes and also regulates other genes involved in the cell stress response and in metal homeostasis. In resting cells, MTF-1 localizes to both the cytoplasm and the nucleus but quantitatively accumulates in the nucleus upon metal load and under other stress conditions. Here we show that within the DNA-binding domain, a region spanning zinc fingers 1 to 3 (amino acids [aa] 137 to 228 in human MTF-1) harbors a nonconventional nuclear localization signal. This protein segment confers constitutive nuclear localization to a cytoplasmic marker protein. The deletion of the three zinc fingers impairs nuclear localization. The export of MTF-1 to the cytoplasm is controlled by a classical nuclear export signal (NES) embedded in the acidic activation domain. We show that this activation domain confers metal inducibility in distinct cell types when fused to a heterologous DNA-binding domain. Furthermore, the cause of a previously described stronger inducibility of human versus mouse MTF-1 could be narrowed down to a 3-aa difference in the NES; “humanizing” mouse MTF-1 at these three positions enhanced its metal inducibility to the level of human MTF-1.

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The monopartite nuclear localization signal of autoimmune regulator mediates its nuclear import and interaction with multiple importin alpha molecules

FEBS Journal ◽

10.1111/j.1742-4658.2005.05065.x ◽

2006 ◽

Vol 273 (2) ◽

pp. 315-324 ◽

Cited By ~ 25

Author(s):

Tanja Ilmarinen ◽

Krister Melen ◽

Hannele Kangas ◽

Ilkka Julkunen ◽

Ismo Ulmanen ◽

...

Keyword(s):

Nuclear Localization ◽

Nuclear Import ◽

Nuclear Localization Signal ◽

Autoimmune Regulator ◽

Importin Alpha ◽

Localization Signal

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Dynamic localization of the nuclear import receptor and its interactions with transport factors.

The Journal of Cell Biology ◽

10.1083/jcb.133.6.1163 ◽

1996 ◽

Vol 133 (6) ◽

pp. 1163-1176 ◽

Cited By ~ 86

Author(s):

D M Koepp ◽

D H Wong ◽

A H Corbett ◽

P A Silver

Keyword(s):

Nuclear Localization ◽

Nuclear Localization Signal ◽

Protein Import ◽

Genetic Interaction ◽

Nuclear Transport ◽

Nuclear Pore ◽

Importin Beta ◽

Importin Alpha ◽

Localization Signal

Characterization of the interactions between soluble factors required for nuclear transport is key to understanding the process of nuclear trafficking. Using a synthetic lethal screen with the rna1-1 strain, we have identified a genetic interaction between Rna1p, a GTPase activating protein required for nuclear transport, and yeast importin-beta, a component of the nuclear localization signal receptor. By the use of fusion proteins, we demonstrate that Rna1p physically interacts with importin-beta. Mutants in importin-beta exhibit in vivo nuclear protein import defects, and importin-beta localizes to the nuclear envelope along with other proteins associated with the nuclear pore complex. In addition, we present evidence that importin-alpha, but not importin-beta, mislocalizes to the nucleus in cells where the GTPase Ran is likely to be in the GDP-bound state. We suggest a model of nuclear transport in which Ran-mediated hydrolysis of GTP is necessary for the import of importin-alpha and the nuclear localization signal-bearing substrate into the nucleus, while exchange of GDP for GTP on Ran is required for the export of both mRNA and importin-alpha from the nucleus.

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