guanine nucleotide exchange fac-
tor ECT2 (see the Focus by Shin
et al.). Disrupting this mechanism
increased the toxicity of DNA-
damaging agents in cultured
cells. These findings may lead
to new ways to overcome tumor
resistance to DNA-damaging
chemotherapeutics. —LKF
Sci. Signal. 15 , eabh2290,
eabm6211 (2022).HEAVY FERMIONS
A gentle reconstruction
Changes in the volume of a mate-
rial’s Fermi surface are typically
associated with the breaking
of symmetry. Maksimovic et al.
found evidence for an unusual
type of this Fermi surface recon-
struction, one without symmetry
breaking, in the heavy fermion
compound cerium cobalt indium
(CeCoIn 5 ). Doping the material
with tin led to abrupt changes in
Hall effect, quantum oscillation,
and photoemission signals. The
researchers interpret the findings
in terms of the delocalization
of f-electrons associated with
cerium atoms. —JS
Science, aaz4566, this issue p. 76BATTERIES
Preservation of
cycling behavior
Understanding the changes in
interfaces between electrode
and electrolyte during battery
cycling, including the formation
of the solid-electrolyte interphase
(SEI), is key to the development
of longer-lasting batteries. Z.
Zhang et al. adapted a thin-film
vitrification method to ensure the
preservation of liquid electrolyte
so that the samples taken for
analysis using microscopy and
spectroscopy better reflect the
state of the battery during opera-
tion. A key finding is that the SEI
is in a swollen state, in contrast to
current belief that it only contains
solid inorganic species and
polymers. The extent of swelling
can affect transport through the
SEI, which thickens with time,
and thus might also decrease the
amount of free electrolyte avail-
able for battery cycling. —MSL
Science, abi8703, this issue p. 66DNA DAMAGE
Double duty for DNA-PK
DNA-dependent protein kinase
(DNA-PK) coordinates the
DNA damage response and
also promotes cell survival and
resistance to chemotherapy
through activation of the kinase
AKT. Liu et al. found that DNA-PK
mediates a phosphorylation event
that activates AKT in a manner
dependent on mechanistic target
of rapamycin complex 2 and thePLANETARY EVOLUTION
Abrupt oxygenation
of Earth
The amount of oxygen in Earth’s
early atmosphere increased
abruptly 2.3 billion years ago
during the “Great Oxygenation
Event,” but questions remain as
to whether there were earlier,
transient “whiffs” of oxygen
before then, perhaps related
to early photosynthesis. A
new study by Slotznick et al.
examined samples from an
area in western Australia where
others found what they inter-
preted as evidence of transient
appearances of oxygen as early
as 2.5 billion years ago. The new,
microanalytical studies reveal no
evidence of early oxygenation,
leading the authors to conclude
that oxygen levels on Earth
were negligible until the Great
Oxygenation Event. —KVH
Sci. Adv. 10.1126/
sciadv.abj7190 (2022). IMAGE: JOSE CALVO/SCIENCE SOURCE36 7 JANUARY 2022 • VOL 375 ISSUE 6576 science.org SCIENCE
NEUROSCIENCEDendritic spines’ electrical function?
D
endritic spines are small protrusions that cover the dendrites of most neurons in the
brain. Their electrical properties are still controversially discussed. Cornejo et al. used
an array of techniques to investigate the degree of voltage attenuation by dendritic
spine necks in pyramidal neurons of the mouse neocortex. Spines not only synchro-
nously depolarized in response to backpropagating action potentials, but local and
transient depolarization also occurred. Isolated depolarization in individual spines reflected
localized synaptic activation. A significant voltage gradient between dendritic spine and
dendrite indicated that spines may constitute elementary electric compartments. The spine
neck resistance is thus not negligible and may substantially contribute to the regulation of
synaptic efficacy in the central nervous system. —PRS Science, abg0501, this issue p. 82Dendritic spines, seen here on a Purkinje neuron, experience compartmentalized voltage dynamics.IN SCIENCE JOURNALS
RESEARCH
Edited by Michael Funk