Subpopulation-proteomics in prokaryotic populations

Clonal microbial cells do not behave in an identical manner and form subpopulations during cultivation. Besides varying micro-environmental conditions, cell inherent features like cell cycle dependent localization and concentration of regulatory proteins as well as epigenetic properties are well accepted mechanisms creating cell heterogeneity. Another suspected reason is molecular noise on the transcriptional and translational level. A promising tool to unravel reasons for cell heterogeneity is the combination of cell sorting and subpopulation proteomics. This review summarizes recent developments in prokaryotic single-cell analytics and provides a workflow for selection of single cells, low cell number mass spectrometry, and proteomics evaluation. This approach is useful for understanding the dependency of individual cell decisions on inherent protein profiles.