high-resolution-complexome-profiling-by-cryoslicing-bn-ms-analysis

High-Resolution Complexome Profiling by Cryoslicing BN-MS Analysis

Proteins generally exert biological functions through interactions with other proteins, either in dynamic protein assemblies or as a part of stably formed ...

University of Freiburg, Freiburg, Germany

Signalling Research Centres BIOSS and CIBSS, Freiburg, Germany

Logopharm GmbH, Germany

Native AMPA receptors (AMPARs) in the mammalian brain are macromolecular complexes whose functional characteristics vary across the different brain regions and change during postnatal development or in response to neuronal activity. The structural and functional properties of the AMPARs are determined by their proteome, the ensemble of their protein building blocks. Here we use high-resolution quantitative mass spectrometry to analyze the entire pool of AMPARs affinity-isolated from distinct brain regions, selected sets of neurons, and whole brains at distinct stages of postnatal development. These analyses show that the AMPAR proteome is dynamic in both space and time: AMPARs exhibit profound region specificity in their architecture and the constituents building their core and periphery. Likewise, AMPARs exchange many of their building blocks during postnatal development. These results provide a unique resource and detailed contextual data sets for the analysis of native AMPAR complexes and their role in excitatory neurotransmission.

Regional diversity and developmental dynamics of the AMPA-receptor proteome in the mammalian brain.

Blue native (BN) gel electrophoresis is a powerful method for protein separation. Combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), it enables large scale identification of protein complexes and their subunits. Current BN-MS approaches, however, are limited in size resolution, comprehensiveness, and quantification. Here, we present a new methodology combining defined sub-millimeter slicing of BN gels by a cryo-microtome with high performance LC-MS/MS and label-free quantification of protein amounts. Application of this cryo-slicing BN-MS approach to mitochondria from rat brain demonstrated a high degree of comprehensiveness, accuracy, and size resolution. The technique provided abundance-mass profiles for 774 mitochondrial proteins, including all canonical subunits of the oxidative respiratory chain assembled into 13 distinct (super-)complexes. Moreover, the data revealed COX7R as a constitutive subunit of distinct super-complexes and identified novel assemblies of voltage-dependent anion channels/porins and TOM proteins. Together, cryo-slicing BN-MS enables quantitative profiling of complexomes with resolution close to the limits of native gel electrophoresis. 

Article	Year
Regional diversity and developmental dynamics of the AMPA-receptor proteome in the mammalian brain. Neuron\| PubMed ID: 25242221	2014
Cryo-slicing Blue Native-Mass Spectrometry (csBN-MS), a Novel Technology for High Resolution Complexome Profiling. Molecular & cellular proteomics : MCP\| PubMed ID: 26598645	2016

Uwe Schulte

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