Fig. 1.

Domain structure and function of Atxn2. (a) Known functional motifs are diagrammed for ataxin-2 (Atxn2) protein with their amino acid (aa) residue numbering. Identified domains include polyglutamine tract (Q; aa 166–187), SRC homology 3 domain binding motifs 1 (SBM1; aa 117–126) and 2 (SBM2; aa 587–596), Like sm domain (Lsm; aa 254–345), Lsm-associated domain (LsmAD; aa 353–475), and poly(A)-binding protein (PABP) interacting motif 2 (PAM2; aa 908–925). (b) Atxn2 interacts directly or indirectly with various RNA-binding proteins (RBP), such as STAU1 protein, and also with PABP. These proteins are involved in translation and stress granule formation processes. Polyglutamine expansion in Atxn2 protein may interrupt these interactions and lead to the disturbed RNA metabolism. Modified from Paulson et al. [3] and Scoles and Pulst [4]