Figure 9.

Structure of RACK1 bound to the 40S eukaryotic ribosomal subunit and interaction with co-associated ribosomal proteins. (A) Surface rendition of T. thermophila (PDB: 2XZN) 40S subunit: rRNA (white); RACK1 coloured as in Figure 2A/B; ribosomal proteins are shown in grey with the exception of those in direct contact with RACK1 -- rpS3e (light brown), rpS16e (light blue), rpS17e (pale cyan). (B) As (A) but with 90° rotation about the y-axis; position of mRNA exit tunnel is marked (dashed oval). (C) Detail of ribosome-bound RACK1 structure, highlighting PKC-binding loci on blades 2 and 6; RACK1 and rRNA are shown in ribbon format, interacting ribosomal proteins are surface-rendered. (D) Detail of key contacts between RACK1 residues (italicised) and rpS17e residues (non-italicised): D27 (rpS17e) forms a salt bridge with R47 (RACK1); F30 (rpS17e) packs against aromatic RACK1 side chains (W, Y, W, W). R47 (RACK1) engages rRNA backbone phosphates.