Plectin repeats and modules: strategic cysteines and their presumed impact on cytolinker functions
Janda, L., Damborsky, J., Rezniczek, G.A., Wiche, B.
BIOASSAYS 23: 1064-1069 (2001)
Plectin, a member of the cytolinkers protein family, plays a crucial role in cells as a stabilizing element of cells against mechanical stress. Its absence results in muscular dystrophy, skin blistering, and signs of neuropathy. The C-terminus domain of plectin contains several highly homologous repeat domains that also occur in other cytolinkers. Secondary structure analysis revealed that the building block of these domains, the PLEC repeat, is similar to the ankyrin repeat. We present a model, which comprises ~1900 amino acid, could be stabilized to maintain its structural integrity even udenr extensive mechanical stress. In this model, larger solenoid modules formed from PLEC repeats can be disulphide-bridged via conserved cysteines. Our hypothesis suggests that this process could be mediated by cytoplasmic NOS-generated products, such as the radical peroxynitrite. Reinforcement of molecular structure would provide a rationale why during exercising or physiological stress radicals are formed without necessarily being deleterious.