November 2008 Volume 15 Number 11, pp 1127 - 1231
Visit Nature Structural & Molecular Biology online to browse the
journal.
Now available at http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0BBL70EA
Please note that you need to be a subscriber to enjoy full text
access to Nature Structural & Molecular Biology online. To purchase
a subscription, please visit:
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0aAO0Em
Alternatively, to recommend a subscription to your library, please
visit
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0BRu70E6
=====================================================================
Free Access to Featured Cell Research Articles
Available for a Limited Time Only
Act now and take advantage of FREE access to some of the top Cell Research
articles from the past two years. Featured articles cover topics including but
not limited to: apoptosis, stem cells, cell growth and differentiation, signal
transduction, immunology, neurosciences and much more!
Take advantage of this limited time special by visiting
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0B6iA0Eb
=====================================================================
----------------------
EDITORIAL
----------------------
Enlightening biology p1127
This year's Nobel Prize in Chemistry recognized the researchers
whose work literally illuminated biological processes.
doi:10.1038/nsmb1108-1127
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAkx0Ek
----------------------
NEWS AND VIEWS
----------------------
A major switch for the Fanconi anemia DNA damage-response pathway
pp1128 - 1130
The Fanconi anemia pathway is part of the DNA-damage network
including breast cancer-susceptibility proteins BRCA1 and BRCA2.
This pathway is activated by the ataxia telangiectasia and
Rad3-related (ATR) kinase, but the underlying mechanism remains
unclear. A new study demonstrates that a major switch activating
the pathway is the ATR-dependent phosphorylation of FANCI.
Weidong Wang
doi:10.1038/nsmb1108-1128
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAky0El
Integration of an electric-metal sensory experience in the Slo1 BK
channel pp1130 - 1132
The open gate of the BK-type K+ channel is stabilized when the
voltage-sensor domains (VSDs) are activated by depolarization and
the intracellular Mg2+ sensors are occupied. A systematic
investigation reveals that each Mg2+ is bound by the transmembrane
VSD and cytoplasmic ligand-sensing domain from two adjacent subunits,
suggesting that relative positions of sensor and gate domains of BK
channels may differ substantially from those suggested by homology
models.
Frank T Horrigan and Toshinori Hoshi
doi:10.1038/nsmb1108-1130
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAkz0Em
An INKlination for epigenetic control of senescence
pp1133 - 1134
Much has been written and said about the links between the Ink4a-Arf
locus, cellular senescence and stem-cell maintenance. Standing
modestly in the shadows of these superstars of tumor suppression,
the closely linked Ink4b gene is now emerging as a significant player
in these events, and its regulation by a histone demethylase could
provide new insights into how this remarkable locus is controlled.
Gordon Peters
doi:10.1038/nsmb1108-1133
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk10EZ
How to pick a protein and pull at it pp1135 - 1136
In this issue of Nature Structural & Molecular Biology, work on the
bacterial AAA+ machine ClpX provides insight into how the ATPase
subunits exert a translocating force on their substrates.
Tomonao Inobe, Daniel A Kraut and Andreas Matouschek
doi:10.1038/nsmb1108-1135
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk20Ea
----------------------
RESEARCH HIGHLIGHTS
----------------------
Research highlights p1137
Angela K Eggleston, Joshua M Finkelstein, Maria Hodges and Sabbi Lall
doi:10.1038/nsmb1108-1137
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk30Eb
----------------------
ARTICLES
----------------------
FANCI phosphorylation functions as a molecular switch to turn on the
Fanconi anemia pathway pp1138 - 1146
The Fanconi anemia pathway is involved in the signaling of DNA
damage. Several Fanconi anemia proteins have been identified, but
how the pathway is actually activated was unclear. Now, work on
chicken DT40 cells indicates that phosphorylation of FANCI at
multiple sites triggers FANCD2 monoubiquitination and DNA-damage
repair.
Masamichi Ishiai et al.
doi:10.1038/nsmb.1504
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk40Ec
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk50Ed
Pore loops of the AAA+ ClpX machine grip substrates to drive
translocation and unfolding pp1147 - 1151
The bacterial AAA+ ClpX unfolds substrates using the energy from
ATP hydrolysis and delivers them to the associated protease ClpP.
A loop with an aromatic-hydrophobic motif protrudes into the
central pore of the ClpX hexamer and was known to be important for
activity. Now mutational analysis using covalently linked subunits
provides evidence that this loop actually grips the substrate and
undergoes conformational changes to drive its translocation and
unfolding.
Andreas Martin, Tania A Baker and Robert T Sauer
doi:10.1038/nsmb.1503
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk60Ee
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk70Ef
Activation of Slo1 BK channels by Mg2+ coordinated between the
voltage sensor and RCK1 domains pp1152 - 1159
The voltage-sensor and RCK1 domains of BK channels act
synergistically to sense electric and chemical signals.
New data now indicate that the Mg2+-mediated interactions
between these domains occurs between channel subunits,
suggesting a structural arrangement that differs from
other potassium channels.
Huanghe Yang et al.
doi:10.1038/nsmb.1507
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAk80Eg
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlA0Eq
The Janus-faced nature of the C2B domain is fundamental for
synaptotagmin-1 function pp1160 - 1168
The Ca2+ binding loops of the C2A and C2B domains of synaptotagmin-1
are known to be important in Ca2+-triggered neurotransmitter release.
Biophysical and in vivo data now indicate that a basic patch on the
opposite face of the C2B domain has an equally crucial but
Ca2+-independent role.
Mingshan Xue et al.
doi:10.1038/nsmb.1508
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlB0Er
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlC0Es
The H3K36 demethylase Jhdm1b/Kdm2b regulates cell proliferation and
senescence through p15Ink4b pp1169 - 1175
The Ink4a-Arf-Ink4b locus has a role in both senescence and
tumorigenesis, and dysregulation can result in tumorigenesis. The
Jhdm1b Jumonji family protein is now shown to be an H3K36 demethylase
and is implicated in regulating cellular proliferation and senescence
through p15Ink4b.
Jin He, Eric M Kallin, Yu-ichi Tsukada and Yi Zhang
doi:10.1038/nsmb.1499
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlD0Et
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlE0Eu
De novo DNA methylation promoted by G9a prevents reprogramming of
embryonically silenced genes pp1176 - 1183
G9a is involved in gene silencing during early embryonic
development, catalyzing the methylation of H3K9, which results
in heterochromatinization, and also promoting methylation of DNA
de novo. These two G9a activities are now dissected, and de novo
DNA methylation is shown to occur via recruitment of Dnmt3a//3b
and to be necessary and sufficient to prevent reprogramming.
Silvina Epsztejn-Litman et al.
doi:10.1038/nsmb.1476
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlF0Ev
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlG0Ew
Phosphorylation of APOBEC3G by protein kinase A regulates its
interaction with HIV-1 Vif pp1184 - 1191
The antiretroviral cytidine deaminase APOBEC3G inhibits HIV-1
replication, but the enzyme is targeted for degradation by HIV-1
Vif. Protein kinase A activity is known to be elevated in
HIV-1-infected T cells. New data indicate that phosphorylation
of APOBEC3G by protein kinase A renders the protein less susceptible
to Vif-mediated degradation.
Kotaro Shirakawa et al.
doi:10.1038/nsmb.1497
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlH0Ex
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlI0Ey
A quantitative model of transcription factor-activated gene expression
pp1192 - 1198
The effect of transcription factor affinity and accessibility on gene
expression has been difficult to quantify and model. The contribution
of both transcription factor binding affinity and nucleosomes to
tuning and diversification of gene expression output is now
quantitatively uncovered, and a model that can be applied to other
eukaryotic gene expression systems generated.
Harold D Kim and Erin K O'Shea
doi:10.1038/nsmb.1500
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlJ0Ez
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlK0E1
Structural elucidation of a PRP8 core domain from the heart of the
spliceosome pp1199 - 1205
The spliceosome consists of five RNAs and more than 100 associated
proteins. One of these, PRP8, is both one of the largest and most
highly conserved spliceosomal proteins. Previous genetic and
cross-linking data pointed to the importance of domain IV of PRP8
in spliceosome assembly and/or catalysis. Its structure has now been s
olved and found to contain an RNase H fold, suggestive of an RNA
binding surface. The RNA binding data suggest that the PRP8 core
recognizes, rather than a specific sequence, a structure resembling
the four-helix junction proposed for the catalytically active U2/U6
snRNA interaction.
Dustin B Ritchie et al.
doi:10.1038/nsmb.1505
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlL0E2
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlM0E3
Localization of Prp8, Brr2, Snu114 and U4/U6 proteins in the yeast
tri-snRNP by electron microscopy pp1206 - 1212
The tri-snRNP is the largest preassembled unit of the spliceosome,
and its components are key to the splicing reaction. The overall
structure and conformations of the yeast tri-snRNP are now analyzed
by EM, and the general positions of some of its major protein
components mapped.
Irina Hacker et al.
doi:10.1038/nsmb.1506
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlN0E4
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlO0E5
Insights into interferon regulatory factor activation from the crystal
structure of dimeric IRF5 pp1213 - 1220
The interferon regulatory factors (IRFs) are involved in the innate
immune response and are activated by phosphorylation. The structure
of a pseudophosphorylated IRF5 activation domain now reveals
structural changes in the activated form that would turn an
autoinhibitory region into a dimerization interface. In vivo analysis
supports the relevance of such a dimer to transcriptional activation.
Weijun Chen et al.
doi:10.1038/nsmb.1496
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlP0E6
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlQ0E7
----------------------
BRIEF COMMUNICATION
----------------------
Structural basis for exon recognition by a group II intron
pp1221 - 1222
Group II introns are retroelements that have invaded the genomes of
many prokaryotes and eukaryotes. The structure of a self-spliced
group IIC intron cocrystallized with ligated exons (the target
substrate) reveals the metal ions that have a role in catalysis and
the intron sequences that are important in exon recognition in group
II introns.
Navtej Toor, Kanagalaghatta Rajashankar, Kevin S Keating and Anna
Marie Pyle
doi:10.1038/nsmb.1509
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlR0E8
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlS0EA
----------------------
ANALYSES
----------------------
The 'glutamate switch' provides a link between ATPase activity and
ligand binding in AAA+ proteins pp1223 - 1227
The ATPase activity of AAA+ proteins is regulated by their
interaction with ligands, but depending on the particular protein
it can be stimulated or inhibited, and the mechanism for such
control remained unclear. An analysis of previous structural data
on various AAA+ proteins now reveals that a conserved glutamate
residue adopts two conformations and and thus regulates the ATPase
activity.
Xiaodong Zhang and Dale B Wigley
doi:10.1038/nsmb.1501
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlT0EB
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlU0EC
An equivalent metal ion in one- and two-metal-ion catalysis
pp1228 - 1231
Most known nucleotidyl-transfer enzymes use two metal ions for
catalysis, but some enzymes use only one divalent cation in their
active sites. A comparative analysis of previously available
structural data reveals that the one-metal-ion enzymes use a similar
mechanism to coordinate their single metal ion, which corresponds,
functionally and structurally, to metal ion B in the two-metal-ion
enzymes.
Wei Yang
doi:10.1038/nsmb.1502
Abstract: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlV0ED
Article: http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0CAlW0EE
=====================================================================
Natureevents Directory 2009
Want to inform a potential one million scientists about your scientific events, courses and conferences?
Natureevents Directory 2009 is now in its 10th year.
To find out how to be included, visit
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0B6rM0Ew
=====================================================================
You have been sent this Table of Contents Alert because you have
opted in to receive it. You can change or discontinue your e-mail
alerts at any time, by modifying your preferences on your nature.com
account at:
http://ealerts.nature.com/cgi-bin24/DM/y/eoe60Xztnp0Hjh0Zzu0EG
(You will need to log in to be recognised as a nature.com registrant).
For further technical assistance, please contact our registration
department:
registration@nature.com
For print subscription enquiries, please contact our subscription
department:
subscriptions@nature.com
For other enquiries, please contact our customer feedback department:
feedback@nature.com
Nature Publishing Group | 75 Varick Street, 9th Floor | New York |
NY 10013-1917 | USA
Nature Publishing Group's worldwide offices:
London - Paris - Munich - New Delhi - Tokyo - Melbourne -
San Diego - San Francisco - Washington - New York - Boston
(c) Copyright 2008 Nature Publishing Group
=====================================================================
