Type C mutation of nucleophosmin 1 acute myeloid leukemia: Consequences of intrinsic disorder

Background: Nucleophosmin 1 (NPM1) protein is a multifunctional nucleolar chaperone and its gene is the most frequently mutated in Acute Myeloid Leukemia (AML). AML mutations cause the unfolding of the C-terminal domain (CTD) and the protein delocalizing in the cytosol (NPM1c+). Marked aggregation endowed with an amyloid character was assessed as consequences of mutations. Scope: Herein we analyzed the effects of type C mutation on two protein regions: i) a N-terminal extended version of the CTD, named Cterm_mutC and ii) a shorter polypeptide including the sequences of the second and third helices of the CTD, named H2_mutC. Major conclusions: Both demonstrated able to self-assembly with different kinetics and conformational intermediates and to provide fibers presenting large flexible regions. General significance: The present study adds a new piece of knowledge to the effects of AML-mutations on structural biology of Nucleophosmin 1, that could be exploited in therapeutic interventions targeting selectively NPMc+.