Abstract
The giant sarcomeric protein titin contains a protein kinase domain (TK) ideally positioned to sense mechanical load. We identified a signaling complex where TK interacts with the zinc-finger protein nbr1 through a mechanically inducible conformation. Nbr1 targets the ubiquitin-associated p62/SQSTM1 to sarcomeres, and p62 in turn interacts with MuRF2, a muscle-specific RING-B-box E3 ligase and ligand of the transactivation domain of the serum response transcription factor (SRF). Nuclear translocation of MuRF2 was induced by mechanical inactivity and caused reduction of nuclear SRF and repression of transcription. A human mutation in the titin protein kinase domain causes hereditary muscle disease by disrupting this pathway.
MeSH Terms
Amino Acid Sequence
Amino Acid Substitution
Animals
Catalytic Domain
Cell Line
Cell Nucleus/metabolism
Connectin
Gene Expression Regulation
Heat-Shock Proteins/metabolism
Humans
Intracellular Signaling Peptides and Proteins
Ligands
Mice
Mice, Inbred C3H
Molecular Sequence Data
Muscle Proteins/chemistry,genetics,metabolism
Muscle, Skeletal/metabolism
Muscular Diseases/genetics
Mutation
Myocytes, Cardiac/metabolism
Protein Binding
Protein Conformation
Protein Kinases/chemistry,genetics,metabolism
Protein Structure, Tertiary
Proteins/metabolism
Rats
Respiratory Insufficiency/genetics,metabolism
Sarcomeres/metabolism
Sequestosome-1 Protein
Serum Response Factor/metabolism
Signal Transduction
Two-Hybrid System Techniques
Ubiquitin-Protein Ligases/metabolism
Chemicals
Connectin
Heat-Shock Proteins
Intracellular Signaling Peptides and Proteins
Ligands
Muscle Proteins
NBR1 protein, human
Nbr1 protein, rat
Proteins
Sequestosome-1 Protein
Serum Response Factor
Sqstm1 protein, rat
TTN protein, human
Ubiquitin-Protein Ligases
Protein Kinases
Authors & Affiliations
19 authors, click to expand affiliations / ORCID
Lange Stephan
Muscle Signalling and Development, Randall Division, King's College London, London SE1 1UL, UK.
Xiang Fengqing
Yakovenko Andrey
Vihola Anna
Hackman Peter
Rostkova Elena
Kristensen Jakob
Brandmeier Birgit
Franzen Gereon
Hedberg Birgitta
Gunnarsson Lars Gunnar
Hughes Simon M
Marchand Sylvie
Sejersen Thomas
Richard Isabelle
Edström Lars
Ehler Elisabeth
Udd Bjarne
Gautel Mathias