Fig. 7: OB-DA proteome identification in DAT-Cre::6xMetRS*.

a, The workflow for labeling and purification of OB-DA proteins. In vivo protein labeling was performed by daily IP injection of ANL for 2 weeks in DAT-Cre::6xMetRS* mice (ANL, n = 7; no-ANL control, n = 5). OB tissue was collected, and ANL-containing proteins were clicked, purified and quantified by LC–MS. b, Confocal microscopy images showing the ANL-labeled proteins by FUNCAT in the OB-DA neurons from DAT-Cre::6xMetRS* mice. Scale bars, 200 μM, 40 μM (DAT-Cre::6x-MetRS* detail) and 30 μM (6x-MetRS* detail). c, A box plot showing that most proteins of the OB-DA neuron samples are enriched over the control samples. n numbers shown above each box plot. d, A bar plot showing protein group identifications of the quantified OB-DA proteins. The OB-DA neuron proteome was defined by either exclusive identification or enrichment in ANL-labeled samples over the unlabeled controls. See also Supplementary Fig. 5a. e, Box plots displaying brain disease-associated and/or previously reported DA proteins identified in the DA-OB proteome. n.d., not found. f, Overrepresentation analysis showing enriched terms for the DA proteome according to PaGenBase, transcription factor (TF) ChIP-seq data from ENCODE and cellular pathways by PANTHER. g, Gene Ontology overrepresentation displaying the top ten terms for the DA proteome, based on gene ontology cellular compartment (GOCC) and biological process (GOBP) annotations (FDR <0.05). h, A volcano plot comparing proteins quantified in labeled samples with the unlabeled controls. Significantly enriched protein groups (80% valid value in labeled condition, at least 1.5-fold enrichment, FDR <0.01) are highlighted in yellow. Furthermore, color indicates proteins matching the DA proteome of striatal synapses or PD-associated genes (UniProt KW: KW-0907). i, A Venn diagram highlighting the overlap of the OB-DA proteome with DA proteins of striatal (str) synapses or PD-associated genes (UniProt KW: KW-0907). Genes shared between the OB-DA neuron proteome and the striatal DA synapse proteome from van Oostrum et al.³⁰ show an enrichment in proteasome and neurodegenerative disease proteins (Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, FDR <0.05). Box plots in c and e specify the median and first and third quartiles, and whiskers extend to 1.5× interquartile range. Analyses in f and g were done using OB background.