Prof. Dr. Matthias Mann
Protein Interaction Laboratory (www.pil.sdu.dk)
University of Southern Denmark Odense University
DK-5230 Odense M
Abstract
The anticipated availability of virtually all human gene sequences already within a year will usher in the "post genome era" of biology sooner than expected. We now require large-scale experimental approaches which will use the genomic information but add another dimension of information to it. Methods which are already being applied include large scale two hybrid screening (currently for small to medium genome sizes) and large scale expression analysis via DNA chip arrays. Here we discuss an additional approach which is also capable of providing function or at least the cellular role of the genes uncovered in genomic sequencing projects. Advances in mass spectrometry over the last few years now make it possible to identify large numbers of gel separated proteins at minute levels (low femotmole/ low nanogram)(Shevchenko, Jensen et al. 1996; Wilm, Shevchenko et al. 1996). Proteins of interest can be precipitated using gene tagging or antibody methods, revealing interacting proteins on one or two dimensional gels which can then be identified by mass spectrometry (Lamond and Mann 1997; Neubauer, Gottschalk et al. 1997). We show that this technology can be scaled up to large numbers and that significant biological results have already been obtained both in structural protein complexes and in transient complexes such as the ones involved in signalling(Neubauer, King et al. 1998; Yaron, Hatzubai et al. 1998). In principle this technology can lead to a protein interaction map of the cell. The approach should be accompanied by bioinformatics tools which interpret the empirically found interactions. We conclude that mass spectrometry of multi-protein complexes is a valid approach which rapidly yields functional information on open reading frames identified in sequencing projects.
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