Membrane proteomics
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- Research Group
Hanna Eriksson, Johan Lengqvist, Ernesto Silva and Janne Lehtiö.
- External Collaborators
Bengt Persson, Department of Cell and Molecular Biology (CMB),
Karolinska Institutet, Solna, Sweden.
- Description
Membrane proteins constitute about 30-40 percent of all proteins and
include receptors, transporters and various enzymes. Many of the
membrane proteins are involved in the regulation of the communication
between nucleus and cytoplasm and interestingly, 70-80 percent of all
drug targets are membrane proteins. In this project the aim is to
develop methods for membrane proteomics on clinical material. The
method should also be quantitative, since down-stream applications
often involve searching for up- or down regulated proteins.
At KBC we are currently working with a so-called shotgun method. The
whole membrane protein mixture from e.g. cells or tissue is cleaved
into peptides. The peptides are labelled with reporter ions (iTRAQ)
and thereafter separated on an IPG strip according to their pI. The
separation yields ~72 fractions, which are analyzed by LC-MALDI MS/MS.
The iTRAQ reporter ions are used to get quantitative information and
by comparing fragmentation spectra with databases the proteins are
identified. In addition, we compare results with databases consisting
of predicted human membrane proteins only. These databases are made in-
house in collaboration with a bioinformatics group at KI.
