Figure S2.

Composition of NFs. (A) Usually, NF-M or NF-H forms parallel heterodimers with NF-L, which, in turn, arrange into antiparallel heterotetramers through partial overlap of their coiled domains, explaining the lack of polarity in NFs. (B) Eight tetramers assemble into a unit, with the tail domains sticking out further aided by phosphorylation of the M- and H-tails (tail domains of the NF proteins with stippled outlines are left out for clarity). (C) 3D view of the same unit as shown in B, now displaying all tail domains; note that inside-out orientation of tetramers is randomized, since it seems unknown whether this property follows a strict order in real filaments. (D) Proposed dimensions in assembled filaments where units are radially compacted and annealed end to end. Information for this model was taken from Janmey et al., 2003; Kornreich et al., 2015; Szaro and Strong, 2010.