Subcellular spatial proteomics of the heterotrophic nanoflagellate, Cafeteria roenbergensis

Abstract

Cafeteria roenbergensis is the best-studied free-living heterotrophic nanoflagellate, an abundant marine bacterivore and the host of the giant virus CroV, yet almost nothing is known about how its cell is organized. To provide broad insight into the localization of its proteome, we used subcellular spatial proteomics (SSP), based on a label-free version of LOPIT-DC (Localisation of Organelle Proteins by Isotope Tagging after Differential ultraCentrifugation), in which organelles are separated by differential centrifugation and each protein is assigned to a compartment from its abundance profile across fractions. We detected 5,948 proteins (5,889 protein groups), corresponding to 69.7% of the predicted C. roenbergensis proteome, and assigned high-confidence localizations to 2,945 proteins across 14 subcellular compartments, including basal body/cilia, cytosol, ER, Golgi, lysosome, membrane-trafficking, mitochondria, nucleoplasm, nucleus, peroxisome, plasma membrane, proteasome, ribosome, and spliceosome. This study serves as a proteomic dataset to resolve protein compartmentalization in a free-living heterotrophic stramenopile, enabling evolutionary, biological and functional insight and analysis. Investigators interested in using these data prior to publication are encouraged to contact us to avoid overlap and to facilitate coordinated and collaborative use of this resource.