TYRP1 and synucleinopathy: However, while this could argue for a protective role of catB against synucleinopathy, the α-syn truncations produced by in vitro catB cleavage exhibit an increased propensity to aggregate [21] and although lysosome function is essential for degradation of fibrillar α-syn [22], it has also been suggested that catB activity contributes to α-syn toxicity in some cellular models [23].