The discovery of protein chain regions responsible for protein aggregation is an important
result of studying of the molecular mechanisms of prion diseases and different proteinopathies associated
with the formation of pathological aggregations through the prion mechanism. The ability to control
aggregation of proteins could be an important tool in the arsenal of the drug development. Here we
demonstrate, on an example of RNA-binding proteins of the FET family from six animal species (human,
gorilla, pig, mouse, chicken, zebra fish), the possible role of repeats within the disordered regions.
For these proteins, different repeats are revealed in the prion-like (N-terminal disordered) domains,
and in the C-terminal disordered regions, predicted using bioinformatics methods. Moreover, we have found that in
more complex organisms the number of repeats is increased. It can be hypothesized that the presence of a large number of
repeats in the disordered regions in the proteins of the FET-family could both modulate and accelerate the formation of a
dynamic cross-beta structure, and pathological aggregates.