The Peculiarities of Oligomerization of Smooth Muscle Titin and Skeletal Muscle Myosin-Binding Protein C

Protein oligomers are important intermediates in the formation of amyloid fibrils. In amyloidosis, for example, Alzheimer’s disease, oligomers can have a toxic effect on cells. This paper describes the distinctive features of oligomerization of multidomain muscle proteins, smooth muscle titin, and myosin-binding protein C (C-protein) of skeletal muscles consisting of FnIII-like and IgC2-like domains and capable of forming amyloid amorphous aggregates in vitro. Under conditions of low ionic strength (below physiological values), the C-protein formed stable oligomers that were not involved in further aggregation. Smooth muscle titin formed oligomers under conditions of high ionic strength (μ 0.6), which were precursors of amyloid amorphous aggregates of this protein.The results we obtained expand the understanding of the process of protein aggregation.