Fig. 8.
Updated model of the DRC subunit organization and N-DRC interactions with neighboring structures. The locations of the DRC subunits are summarized and colored in the WT nexin–dynein regulatory complex (N-DRC) structure, which is shown in cross-sectional (A), longitudinal front (B), and enlarged bottom (C) views. The structural comparison between the averaged WT axonemal repeat and deletion mutants of DRC subunits or mutant rescues by tagged DRC subunits revealed the architecture of the N-DRC: The core scaffold extends along the entire length of the N-DRC and consists of DRC1 (yellow), DRC2 (dark green), and DRC4 (magenta); with this scaffold associate several functional subunits, i.e., DRC3 (light green), DRC5/6 subcomplex (cyan), DRC7 (red), and DRC8/11 subcomplex (orange). The composition of a few areas within the N-DRC remain unknown (dark blue). Other labels: a–e and g, inner dynein arm isoforms; At, A-tubule; Bt, B-tubule; I1α/I1β/ICLC, α- and β-heavy chain, and intermediate/light-chain complex of I1 dynein; IDA, inner dynein arm; ODA, outer dynein arm; RS, radial spoke.