Fig. 3.

BCL10 unidirectional polymerization. (A) Time-lapse confocal imaging of BCL10 at 4 μM for 2 h with time points at 0, 30, 60, 90, and 120 min, showing unidirectional polymerization. The beginning ends of the filaments are marked with a star, and the red arrowhead shows the elongation ends as a function of time. (B) Schematic representation of a BCL10 filament, showing the direction of BCL10 elongation dictated by a conformational change in the BCL10 subunit. (C) Superposition of BCL10 NMR structure in gray and the cryo-EM model in cyan. (D, Lower) Positively charged surface in a BCL10 filament shows more conformational change between the solution form and the filament form than the (Upper) negatively charged surface. (E) The direction of BCL10 polymerization is labeled in the context of the BCL10 filament structure.