Functional proteomics of transforming growth factor-beta1-stimulated Mv1Lu epithelial cells : Rad51 as a target of TGFbeta1-dependent regulation of DNA repair

• Transforming growth factor-beta (TGFbeta) conveys regulatory signals through multiple intracellular pathways, subsequently affecting various cellular functions. To identify new targets for TGFbeta, we studied the changes in the proteome of Mv1Lu lung epithelial cells in response to TGFbeta1 treatment. Thirty-eight non-abundant protein spots, affected by TGFbeta1, were selected, and proteins were identified by peptide mass-fingerprinting (PMF). Among them, proteins involved in regulation of immune response, apoptosis, regulation of TGFbeta signalling, metabolism and DNA repair were identified. Twenty-eight of the 38 proteins are new targets for TGFbeta1, thus suggesting novel ways of integration of TGFbeta signalling in intracellular regulatory processes. We show that TGFbeta1-dependent decrease in expression of one of the new targets, Rad51, correlates with a decrease in DNA repair efficiency. This was evaluated by formation of nuclear Rad51-containing DNA repair complexes in response to DNA damage, by single cell gel electrophoresis and by cell survival assay. The TGFbeta1-dependent inhibition of DNA repair was reversed by ectopic overexpression of Rad51. Therefore, TGFbeta can promote DNA instability through down-regulation of Rad51 and inhibition of DNA repair.

Nyckelord

Animals

Apoptosis/genetics

Breast Neoplasms/pathology

Cell Cycle Proteins/biosynthesis/genetics

Cell Division/genetics

Cell Line/drug effects/metabolism

Cytoskeletal Proteins/biosynthesis/genetics

DNA Repair/genetics/*physiology

DNA-Binding Proteins/deficiency/*physiology

Electrophoresis; Gel; Two-Dimensional

Epithelial Cells/drug effects

Female

Fibroblasts/drug effects/metabolism

Gene Expression Profiling

Gene Expression Regulation/*drug effects

Humans

Isoelectric Focusing

Lung/*cytology

Mice

Mink

Peptide Mapping

Proteome

Rad51 Recombinase

Recombinant Fusion Proteins/metabolism/pharmacology

Signal Transduction/drug effects

Smad2 Protein

Smad3 Protein

Trans-Activators/deficiency

Transcription; Genetic/genetics

Transforming Growth Factor beta/*pharmacology

Transforming Growth Factor beta1

Tumor Cells; Cultured/drug effects/metabolism

Publikations- och innehållstyp

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