The cover illustration is an overview of the interactions of the Arabidopsis thaliana (right) chloroplast signal recognition particle (cpSRP) components and substrate as determined from an immobilized peptide library (shown in the background). cpSRP54 is shown in blue, and cpSRP43 in a heterodimeric model (left) supported by data in the paper by Groves et al., pages 27778-27786.27778.