New insights into the molecular basis of desmoplakin- and desmin-related cardiomyopathies

Authors:
Lapouge K, Fontao L, Champliaud MF, Jaunin F, Frias MA, Favre B, Paulin D, Green KJ, Borradori L
In:
Source: J Cell Sci
Publication Date: (2006)
Issue: 119(Pt 23): 4974-85
Research Area:
Cardiovascular
Cells used in publication:
Cardiomyocyte (R-CM), rat
Species: rat
Tissue Origin: heart
Platform:
Nucleofector® I/II/2b
Abstract
Desmosomes are intercellular adhesive complexes that anchor the intermediate filament cytoskeleton to the cell membrane in epithelia and cardiac muscle cells. The desmosomal component desmoplakin plays a key role in tethering various intermediate filament networks through its C-terminal plakin repeat domain. To gain better insight into the cytoskeletal organization of cardiomyocytes, we investigated the association of desmoplakin with desmin by cell transfection, yeast two-hybrid, and/or in vitro binding assays. The results indicate that the association of desmoplakin with desmin depends on sequences within the linker region and C-terminal extremity of desmoplakin, where the B and C subdomains contribute to efficient binding; a potentially phosphorylatable serine residue in the C-terminal extremity of desmoplakin affects its association with desmin; the interaction of desmoplakin with non-filamentous desmin requires sequences contained within the desmin C-terminal rod portion and tail domain in yeast, whereas in in vitro binding studies the desmin tail is dispensable for association; and mutations in either the C-terminus of desmoplakin or the desmin tail linked to inherited cardiomyopathy seem to impair desmoplakindesmin interaction. These studies increase our understanding of desmoplakin-intermediate filament interactions, which are important for maintenance of cytoarchitecture in cardiomyocytes, and give new insights into the molecular basis of desmoplakin- and desmin-related human diseases.