3 research outputs found
Reduced purine biosynthesis in humans after their divergence from Neandertals
We analyze the metabolomes of humans, chimpanzees, and macaques in muscle, kidney and three different regions of the brain. Although several compounds in amino acid metabolism occur at either higher or lower concentrations in humans than in the other primates, metabolites downstream of adenylosuccinate lyase, which catalyzes two reactions in purine synthesis, occur at lower concentrations in humans. This enzyme carries an amino acid substitution that is present in all humans today but absent in Neandertals. By introducing the modern human substitution into the genomes of mice, as well as the ancestral, Neandertal-like substitution into the genomes of human cells, we show that this amino acid substitution contributes to much or all of the reduction of de novo synthesis of purines in humans
Deep and Precise Quantification of the Mouse Synaptosomal Proteome Reveals Substantial Remodeling during Postnatal Maturation
During
postnatal murine maturation, behavioral patterns emerge
and become shaped by experience-dependent adaptations. During the
same period, the morphology of dendritic spines, the morphological
correlates of excitatory synapses, is known to change, and there is
evidence of concurrent alterations of the synaptosomal protein machinery.
To obtain comprehensive and quantitative insights in the developmental
regulation of the proteome of synapses, we prepared cortical synaptosomal
fractions from a total of 16 individual juvenile and adult mouse brains
(age 3 or 8 weeks, respectively). We then applied peptide-based iTRAQ
labeling (four pools of 4 animals) and high-resolution two-dimensional
peptide fractionation (99 SCX fractions and 3 h reversed-phase gradients)
using a hybrid CID–HCD acquisition method on a Velos Orbitrap
mass spectrometer to identify a comprehensive set of synaptic proteins
and to quantify changes in protein expression. We obtained a data
set tracking expression levels of 3500 proteins mapping to 3427 NCBI
GeneIDs during development with complete quantification data available
for 3422 GeneIDs, which, to the best of our knowledge, constitutes
the deepest coverage of the synaptosome proteome to date. The inclusion
of biological replicates in a single mass spectrometry analysis demonstrated
both high reproducibility of our synaptosome preparation method as
well as high precision of our quantitative data (correlation coefficient <i>R</i> = 0.87 for the biological replicates). To evaluate the
validity of our data, the developmental regulation of eight proteins
identified in our analysis was confirmed independently using western
blotting. A gene ontology analysis confirmed the synaptosomal nature
of a large fraction of identified proteins. Of note, the set of the
most strongly regulated proteins revealed candidates involved in neurological
processes in health and disease states. This highlights the fact that
developmentally regulated proteins can play additional roles in neurological
disease processes. All data have been deposited to the ProteomeXchange
with identifier PXD000552