1983
Ph.D. - University of Regensburg, Germany
1984 - 1986
PostDoc - Biocenter, Basel, Switzerland (Prof. G. Schatz)
1986 - 1994
Group Leader - European Molecular Biology Laboratory
(EMBL) Heidelberg, Germany, Cell Biology
11.07.1990
Habilitation in Biochemistry - University of Regensburg,
Germany
since 1995
Full Professor - BZH
2003 - 2005
Director - BZH
Ed Hurt
The nuclear pore complex
and its link to mRNP and ribosome biogenesis
Goal
and metazoans, are believed to be the building
Our group performs research with the goal
blocks of the NPC. Currently, the reconstitution of
to elucidate the structure and function of the
these modules is a major challenge in this field.
nuclear pore complex and the mechanism of
Nuclear mRNA export depends on the formation
how mRNPs and ribosomal subunits form
of transport-competent mRNPs that leave the
in the nucleus and are exported to the cyto-
nucleus through nuclear pore complexes (NPCs).
plasm.
Transcription-export complexes (TREXs) composed of factors, which fucntion in transcription
14
Background
and mRNA export, were discovered in the past.
Nuclear pore complexes (NPCs) are the sole me-
These findings indicated that mRNA export fac-
diator of transport between the nucleus and the cy-
tors can be loaded onto the nascent mRNA dur-
toplasm. Embedded into the double nuclear mem-
ing transcription. In addition, it has been shown
brane, this huge assembly exhibits an eight-fold
that a gene locus can be tethered to the nuclear
rotational symmetry with distinct substructures,
envelope to either promote transcription or couple
including the spoke-ring complex, cytoplasmic
transcription with mRNA processing and export.
pore filaments and the nuclear basket. The core
The identification of Sus1 that is assembled into
structure also contains a central channel through
two complexes, a transcription complex (SAGA)
which nucleocytoplasmic transport occurs. The
and an NPC-associated export complex termed
NPC consists of multiple (8, 16 or 32) copies of ~
TREX-2, suggested a physical coupling of acti-
30 different proteins named nucleoporins. While
vated genes to the nuclear side of the NPC.
a few of them are located asymmetrically on ei-
Eukaryotic ribosome formation in the nucleus is a
ther the nucleoplasmic or cytoplasmic side, most
highly dynamic process, which involves the tran-
of the nucleoporins are distributed symmetrically
sient interaction of more than 200 non-ribosomal
within the core structure of the NPC. The major-
factors with the evolving pre-ribosomal particle in
ity of nucleoporins are part of discrete and stable
the nucleus. Biogenesis and export of ribosomal
subcomplexes, which arrange in a still unknown
subunits has been analyzed in the past with the
way within the NPC scaffold. These conserved
help of functional GFP-tagged ribosomal proteins,
complexes, which have been described for yeast
which served as reporters to perform genetic
Ed Hurt
screens for ribosomal export mutants. However,
it in collaboration with Peer Bork’s group (EMBL
these studies not only yielded ribosome export
Heidelberg). Comparison of the thermophile pro-
factors, but also a number of biogenesis factors,
teome with several proteomes of closely related
which act ‘upstream’ of ribosome export. Moreover,
mesophilic filamentous fungi gave insight into
isolation of pre-ribosomal particles along the path
eukaryotic protein adaptation towards thermoph-
from the nucleolus to the cytoplasm yielded bio-
ily. Subsequently, we used a model protein, Arx1
chemical “snapshots” of the dynamic nascent 60S
from C. thermophilum (ctArx1) and its mesophilic
and 40S subunits. Subsequently, a few of these
counterpart C. globosum (cgArx1) to demonstrate
pre-ribosomal particles were analyzed by EM. In
their different thermostabilities, corresponding to
addition, in vitro assays were developed, which
the optimal growth temperatures of these organ-
allowed to monitor pre-ribosome maturation both
isms. The crystal structure of ctArx1 revealed the
by structural and biochemical means. The chal-
position of residues possibly contributing to ther-
lenge in this field remains to assign roles to these
mo-adaptation (Figure 1). Subsequently, several
ca. 200 ribosome biogenesis factors.
other thermophilic proteins were expressed (also
in collaboration with other labs interested in ther-
Research Highlights
mophilic orthologs), which in many cases allowed
Despite numerous efforts to elucidate the archi-
to perform successful biochemical and structural
tecture and function of the NPC, the principles
studies, including in vitro reconstitution, electron
that govern the assembly of the nucleoporins
microscopy and X-ray crystallography.
into the NPC remain poorly understood. The ma-
In addition, we exploited the thermophilic Nups for
jor obstacle is the purification of nucleoporins
in vitro reconstitution. For these studies, we used
in sufficient amounts to perform reconstitution
information from a comprehensive yeast 2-hybrid
studies. We have chosen the thermophilic eu-
analysis performed with yeast Nups, which not
karyote Chaetomium thermophilum, a filamen-
only recapitulated some of the known interac-
tous ascomycete with a growth optimum at 55°C,
tions, but also revealed novel Nup connections.
to gain access to the entire set of thermostable
Notably, nucleoporins derived from the thermo-
nucleoporins, which may have superior biochemi-
philic eukaryote revealed excellent properties in
cal and structural properties when compared to
binding studies, since ctNups could be purified
the mesophilic orthologs. Hence, we sequenced
in significantly higher amounts and exhibited
the genome of C. thermophilum and annotated
increased thermosolubility when compared to
Fig. 1: Thermostability of Arx1 from C. thermophilum and C. globosum. a, Purified Arx1 proteins were incubated for
one hour at the indicated temperatures, before centrifugation into supernatant (S) and pellet (P). b, Crystal structure of
ctArx1 with indicated residues possibly involved in thermostability.
Ed Hurt
15
their yeast counterparts. Using several structural
In our projects related to transcription-coupled
ctNups, whose yeast orthologs were difficult to
mRNA export, we could provide structural in-
handle, we could isolate large amounts and per-
sights into the machineries, which operate at
form successful binding and EM studies (Figure
the interface between transcription and mRNA
2). Moreover, we could reconstitute a long-sought
export. In collaboration with the Stewart group
after NPC subcomplex with these thermophilic
(MRC, Cambridge) we reconstituted and solved
Nups that was not possible to achieve with the
the crystal structure of a subcomplex of TREX-2,
mesophilic Nups from yeast.
which contained Sus1, Cdc31 and Sac3-CID (CID,
Cdc31 Interacting Domain) and could serve as a
scaffold to coordinate the interactions between
transcription and mRNA export machineries at the
NPC. In collaboration with the Zheng lab (Seattle,
USA) we gained structural insight into another
Sus1-containing complex, the Sus1-Sgf11-Ubp8Sgf73 module, which is part of SAGA and acts as
a histone H2B de-ubiquitination (DUB) complex
Fig. 2: EM and 3D reconstruction of ctNup170
(Figures 3). Altogether, these findings highlight
In future studies, we will include further thermo-
the versatile nature of the small Sus1 molecule to
philic Nups in our assembly tests to eventually
act as a clamp, either as a co-factor of the histone
reconstitute the entire NPC. These investigations
DUB module or as a targeting device to tether
could also foster the development of this thermo-
TREX-2 to the NPC.
philic eukaryote as a model organism for the re-
During our studies to investigate the mechanisms
constitution and structural determination of large
of ribosome biogenesis, we obtained insight into
eukaryotic supramolecular assemblies, which
the function of a mechanoenzyme, the Rea1 AAA-
are otherwise difficult to purify from mesophilic
type ATPase, which is involved in ATP-hydrolysis
organisms.
dependent removal of factors from the pre-60S
Fig. 3: . Crystal Structure and model of the Ubp8-Sgf73-Sgf1-Sus1 (DUB) module.
16
Ed Hurt
Thorsten Schäfer, David Tollervey
and Ed Hurt: RNA helicase Prp43 and
its co-factor Pfa1 promote 20S to 18S
rRNA processing catalyzed by the endonuclease Nob1. J. Biol. Chem. 284,
35079-35091 (2009).
Cornelia Ulbrich, Meikel Diepholz,
Jochen Baßler, Dieter Kressler, Brigitte
Pertschy, Kiki Galani, Bettina Böttcher
and Ed Hurt: Mechanochemical
Removal of Ribosome Biogenesis
Factors from Nascent 60S Ribosomal
Subunits. Cell 138, 911-922 (2009).
Fig. 4: . Model of Rea1 function during 60S ribosome biogenesis.
ribosome.
Rea1 consists of an AAA-ATPase
head and a long flexible tail, both of which can
dock to the pre-ribosomal particle. Subsequently
the molecular motor uses ATP to build up a tensile force. This force can be compared to a spiral
spring and is transmitted to the ribosome precursor via the tail (Figure 4). This force could release
late biogenesis factors (such as Rsa4 or the Rix1subcomplex) from the pre-ribosomal particles in
the nucleus, which makes the pre-ribosome competent for export to the cytoplasm.
Recent work revealed that this same mechanoenzyme Rea1 is used twice in the ribosome
biogenesis pathway, acting also in the nucleolus
to pull off other biogenesis factors from an earlier
pre-60S particle. Overall, these studies revealed
mechanistic insight into the complex pathway of
ribosome biogenesis and clarified the function of
some of the participating factors.
Selected Publications 2008 - 2010
Jochen Baßler, Martina Kallas, Matthias Thoms, Cornelia
Ulbrich, Brigitte Pertschy and Ed Hurt: The AAA-ATPase
Rea1 drives removal of biogenesis factors during multiple
stages of 60S ribosome assembly. Mol. Cell 38, 712-721
(2010).
Alwin Köhler, Eric Zimmermann, Maren Schneider, Ed Hurt
and Ning Zheng: Structural basis for assembly and activation
of the heterotetrameric SAGA histone H2B deubiquitinase
module. Cell 141, 606-617 (2010).
Christoph Klöckner, Maren Schneider,
Sheila Lutz, Dieter Kressler, Divyang
Jani, Murray Stewart, Ed Hurt and
Alwin Köhler: Mutational Uncoupling
of Sus1’s role in NPC-targeting of an
mRNA Export Complex and Histone
H2B deubiquitination. J. Biol. Chem.
284, 12049-12056 (2009).
Divyang Jani, Sheila Lutz, Neil J. Marshall, Tamas Fischer,
Alwin Köhler, Andrew M. Ellisdon, Ed Hurt and Murray
Stewart: Sus1, Cdc31 and the Sac3 CID region form a conserved interaction platform that promotes nuclear pore association and mRNA export. Mol. Cell 33, 727-737 (2009).
Michal Skruzny, Claudia Schneider, Attila Rácz, Julan Weng,
David Tollervey and Ed Hurt: An endoribonuclease functionally linked to perinuclear mRNP quality control associates
with the nuclear pore complexes.
PLoS Biology 7, e8 (2009).
Dirk Flemming, Philipp Sarges, Philipp Stelter, Andrea
Hellwig, Bettina Boettcher and Ed Hurt: Two structurally distinct domains of the nucleoporin Nup170 cooperate to tether
a subset of nucleoporins to nuclear pores. J. Cell Biol. 185,
387-395 (2009).
Stefanie Grund, Tamas Fischer, Ghislain G. Cabal, Oreto
Antúnez, José E. Pérez-Ortín and Ed Hurt: The inner nuclear
membrane protein Src1 associates with subtelomeric genes
and alters their regulated gene expression. J. Cell Biol. 182,
897-910 (2008).
Dieter Kressler, Daniela Roser, Brigitte Pertschy and Ed Hurt:
The AAA-ATPase Rix7 powers progression of ribosome biogenesis by stripping Nsa1 from pre-60S particles. J. Cell Biol.
181, 835-844 (2008).
Alwin Köhler, Maren Schneider, Ghislain Cabal, Ulf Nehrbass
and Ed Hurt: An integrative role of Sgf73 in multiple steps of
SAGA-dependent gene gating.
Nat. Cell Biol. 10, 707-15 (2008).
Nils Schrader, Philipp Stelter, Dirk Flemming, Ruth Kunze, Ed
Hurt* and Ingrid Vetter* (*corresponding authors): Structural
basis of the Nic96 subcomplex organization in the nuclear
pore channel.
Mol. Cell 29, 46-55 (2008).
Wei Yao, Malik Lutzmann and Ed Hurt: A versatile interaction platform on the Mex67-Mtr2 receptor creates an overlap between mRNA and ribosome export. EMBO J. 27, 6–16
(2008).
Awards and Honors
2007
Feldberg Prize
2001
Gottfried Wilhelm Leibniz Prize
Since 2010 Editorial Board of EMBO Journal
Dirk Flemming, Karsten Thierbach, Philipp Stelter, Bettina
Boettcher and Ed Hurt: Precise mapping of subunits in multiprotein complexes by a versatile EM-label
Nat. Struct. Mol. Biol.17,775-778 (2010).
Since 2007 Member of ACADEMIA EUROPAEA
Julien Batisse, Claire Batisse, Aidan Budd, Bettina Böttcher
and Ed Hurt: Purification of poly(A)-binding protein Nab2 reveals association with the yeast transcriptome and a messenger ribonucleoprotein (mRNP) core structure. J. Biol.
Chem. 284, 34911-34917 (2009).
Since 1994 Member of EMBO
Brigitte
Pertschy,
Claudia
Schneider,
Maren
Gnädig,
Since 2005 Member of LEOPOLDINA
Ed Hurt
Phone: +49 (0)6221-54 4173
E-mail: [email protected]
Ed Hurt
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