Fig. 2.

Overall workflow for quantitative top-down proteomics analysis of rat brain tissue sections.A, workflow of processing LCM-derived tissue samples with nanoPOTS-TDP platform. B, optical image of rat brain tissue section showing where the small LCM punches were taken in the cortex and hypothalamus regions. C, Venn diagram showing the overlap of quantifiable proteoforms across all samples by TopPIC and TDPortal. D, Zoom-in view of the MALDI intact protein spectrum for the histone H4 proteoform, which was assigned based on identification by nanoPOTS LC-MS/MS. ABC, ammonium bicarbonate; DDM, n-dodecyl-beta-maltoside; LCM, laser capture microdissection; nanoPOTS, nanodroplet processing in one-pot for trace samples; PfCs, proteoform clusters; TDP, top-down proteomics; TopPIC, top-down mass spectrometry–based proteoform identification and characterization.