Putting proteomes into perspective

MAGDEBURG, Germany—Methods designed to analyze a proteome often start by taking proteins out of their cellular context. Fluorescence microscopy alleviates this problem to some extent, but recently researchers at Otto-von-Guericke-University Magdeburg, MelTec GmbH and other institutes took this method one step further, determining the cellular topology of a proteome using multi-epitope-ligand cartography (MELC).

As they described in Nature Biotechnology, MELC works by building a composite fluorescent image of tissues that are treated with cycles of probing and bleaching with labeled antibodies. Using MELC, the researchers mapped 18 cell-surface receptors in peripheral blood cells, reducing each binding event a vector of fluorescence intensity. They thus generated combinatorial molecular phenotypes (CMPs) based on a binary code of 1 (presence), 0 (absence) or * (wild-card).

By comparing CMPs of diseased and healthy tissues, the researchers noted that whereas overall proteomes may not differ between the two cell types, the CMPs differed significantly. The method also allowed them to elucidate protein networks and identify hub proteins for many of these networks, many of which were not previously identified. As such, they see the method as providing a tool to identify candidate target proteins in disease.