Quantitative analysis of proteome coverage and recovery rates for upstream fractionation methods in proteomics.

The proteome of any cell or even any subcellular fraction remains too complex for complete analysis by one dimension of liquid chromatography-tandem mass spectrometry (LC-MS/MS). Hence, to achieve greater depth of coverage for a proteome of interest, most groups routinely subfractionate the sample prior to LC-MS/MS so that the material entering LC-MS/MS is less complex than the original sample. Protein and/or peptide fractionation methods that biochemists have used for decades, such as strong cation exchange chromatography (SCX), isoelectric focusing (IEF) and SDS-PAGE, are the most common prefractionation methods used currently.

Identification of cognate host targets and specific ubiquitylation sites on the Salmonella SPI-1 effector SopB/SigD.

Salmonella enterica is a bacterial pathogen responsible for enteritis and typhoid fever. Virulence is linked to two Salmonella pathogenicity islands (SPI-1 and SPI-2) on the bacterial chromosome, each of which encodes a type III secretion system. While both the SPI-1 and SPI-2 systems secrete an array of effectors into the host, relatively few host proteins have been identified as targets for their effects.

Proteomic analysis of the secretome of Leishmania donovani.

Background: Leishmania and other intracellular pathogens have evolved strategies that support invasion and persistence within host target cells. In some cases the underlying mechanisms involve the export of virulence factors into the host cell cytosol. Previous work from our laboratory identified one such candidate leishmania effector, namely elongation factor-1alpha, to be present in conditioned medium of infectious leishmania as well as within macrophage cytosol after infection.