a period of more than 25 ka corroborate that we
are not dealing with a one-off burst but with a
long tradition that may well stretch back to
the time of the annular construction found in
Bruniquel cave, France (32), dated to 176.5 ±
2.1 ka ago. Dating results for the excavation site
at Cueva de los Aviones, Spain (2), which place
symbolic use of marine shells and mineral pigments by Neandertals at >115 ka ago (33), further
support the antiquity of Neandertal symbolism.
Cave art such as that dated here exists in other
caves of Western Europe and could potentially
be of Neandertal origin as well. Red-painted draperies are found at Les Merveilles (France; panel
VII) (34) and El Castillo (Spain), whereas hand
stencils and linear symbols are ubiquitous and,
when part of complex superimpositions, always
form the base of pictorial stratigraphies. We therefore expect that cave art of Neandertal origin will
eventually be revealed in other areas with Neandertal presence elsewhere in Europe. We also see
no reason to exclude that the behavior will be
equally ancient among coeval non-Neandertal
populations of Africa and Asia.
The authorship of the so-called “transitional”
techno-complexes of Europe, which, like the
Châtelperronian, feature abundant pigments and
objects of personal ornamentation, has long been
the subject of debate (35, 36). Direct or indirect
(via acculturation) assignment to modern humans has been based on an “impossible coincidence” argument—that is, the implausibility that
Neandertals would independently evolve the
behavior just at the time when modern humans
were already in or at the gates of Europe. By
showing that the Châtelperronian is but a late
manifestation of a long-term indigenous tradition of Neandertal symbolic activity, our results
bring closure to this debate.
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This research was financially supported by the Natural Environment
Research Council (UK) (grant NE/K015184/1 to A. W. G.P.), the
National Geographic Society (USA) (grant EC0603-12 to D.L.H.),
the Max Planck Society (Germany), and a Royal Society Wolfson
Research Merit Award (to A. W.G.P.). The work of M.G.-D. was
supported by the Research Group IT622-13 of the Basque
government. We thank the governments of Andalucía, Cantabria,
and Extremadura for sampling permissions. We are grateful
for fieldwork support by J. C. Aguilar, M. Batut, J. R. Bello, D. Garrido,
R. Gutiérrez, and C. Hoffmann. The data described are presented
in the supplementary materials. We dedicate this paper to the
memory of José Antonio Lasheras.
Materials and Methods
Figs. S1 to S42
Tables S1 to S4
25 August 2017; accepted 1 December 2017
Molecular structure of human
P-glycoprotein in the ATP-bound,
Youngjin Kim and Jue Chen*
The multidrug transporter permeability (P)–glycoprotein is an adenosine triphosphate
(ATP)–binding cassette exporter responsible for clinical resistance to chemotherapy.
P-glycoprotein extrudes toxic molecules and drugs from cells through ATP-powered
conformational changes. Despite decades of effort, only the structures of the inward-facing conformation of P-glycoprotein are available. Here we present the structure of
human P-glycoprotein in the outward-facing conformation, determined by cryo–electron
microscopy at 3.4-angstrom resolution. The two nucleotide-binding domains form a closed
dimer occluding two ATP molecules. The drug-binding cavity observed in the inward-facing
structures is reorientated toward the extracellular space and compressed to preclude
substrate binding. This observation indicates that ATP binding, not hydrolysis, promotes
substrate release. The structure evokes a model in which the dynamic nature of
P-glycoprotein enables translocation of a large variety of substrates.
Cancer cells develop resistance to chemically diverse compounds, a phenomenon known as multidrug resistance (MDR). To im- prove the effectiveness of chemotherapy, many laboratories have searched for mech-
anisms that account for MDR. In 1973, Keld Danø
demonstrated that the reduced drug accumu-
lation in tumor cells was energy dependent (1).
In 1976, by labeling cell-surface carbohydrates,
Juliano and Ling identified a glycoprotein en-
riched in colchicine-resistant cells but not in
wild-type cells (2). The protein was named the
permeability (P)–glycoprotein (Pgp) because it
was thought to confer drug resistance by making
the cellular membrane less permeable (3). Ten
years later, the genes responsible for MDR in
human, mouse, and hamster (named MDR genes)
were cloned (4–6), and it was shown that the pro-
tein product of the mdr1 gene was indeed Pgp (7 ).
Pgp is an adenosine triphosphate (ATP)–binding
cassette (ABC) transporter, which uses the ener-
gy from ATP hydrolysis to pump substrates across
the membrane. It contains two transmembrane
domains (TMDs) and two cytoplasmic nucleotide-
binding domains (NBDs) (Fig. 1A). Pgp is ex-
pressed in many membrane “barriers” of the body,
including the blood-brain barrier, gastrointestinal
tract, kidney, liver, ovary, and placenta (2, 8–11).
SCIENCE sciencemag.org 23 FEBRUAR Y 2018 • VOL 359 ISSUE 6378 915
Howard Hughes Medical Institute, The Rockefeller University,
1230 York Avenue, New York, NY 10065, USA.
*Corresponding author. Email: firstname.lastname@example.org
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