Cell fractionation.

International audienceProteins within a cell are localized into specific cellular compartments, allowing compartmentalization of distinct tasks. If we consider lipid bilayers as compartments, then gram-negative bacteria such as Pseudomonas aeruginosa can target proteins to five distinct locations: the cytoplasm, the inner membrane, the periplasm, the outer membrane, and the extracellular environment. In this chapter, we describe how the different compartments can be selectively isolated by a combination of centrifugation and disruption techniques. Fractionation of the cells into subcellular compartments enables protein enrichment and is essential to accurately determine the localization of specific proteins, which is the first step towards understanding the function of a protein in the cell