RT Journal Article SR Electronic T1 Comprehensive characterization of the lung proteasome JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P3860 VO 44 IS Suppl 58 A1 Anne Caniard A1 Juliane Merl A1 Stephanie Hauck A1 Oliver Eickelberg A1 Silke Meiners YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P3860.abstract AB Protein homeostasis is mainly regulated by the proteasome playing an essential role in cellular signaling and immune response. The 20S core particle of the proteasome encloses two sets of three active sites. Upon inflammation, expression of immuno-catalytic subunits is induced. Combinations of standard and immuno-subunits result in formation of constitutive, mixed and immuno-proteasomes. To become fully activated, the 20S core associates with regulatory particles. Whereas catalytic subunits control cleavage specificity, regulators modulate substrate specificity and turnover. Of note, proteasome composition is organ-, cell-, and cell compartment-specific. While changes in proteasome composition are known to be involved in diseases in several organs, they were never studied in the lung.Here, we provide a comprehensive description of the different proteasome complexes in the lung. For that, we isolated proteasome complexes from whole lung homogenates and from A549 cells. A first round of mass spectrometry analyses allowed us to identify all proteasome subunits and regulators, as well as new proteasome interacting proteins. In addition, we characterized several unreported prost-translational modifications (PTM). Currently, we are validating our newly identified proteasome interactors and the role of PTMs for proteasome function. In particular, we are focusing on a new deuibiquitinase, known to be down-regulated in lung cancer; a thioredoxin-like domain protein; and ribosomal subunits.This study will help us to understand the possible involvement of proteasome function in the development of lung diseases, and contributes to the identification of novel therapeutic targets that regulate protein homeostasis.