ZAK activation at the collided ribosome.

ABSTRACT: Ribosome collisions activate the ribotoxic stress response mediated by the MAP3K ZAK, which in turn regulates cell-fate consequences through downstream phosphorylation of the MAPKs p38 and JNK¹. Despite the critical role of ZAK during cellular stress, a mechanistic and structural understanding of ZAK-ribosome interactions and how these lead to activation remain elusive. Here we combine biochemistry and cryo-electron microscopy to discover distinct ZAK-ribosome interactions required for constitutive recruitment and for activation. We find that upon induction of ribosome collisions, interactions between ZAK and the ribosomal protein RACK1 enable its activation by dimerization of its SAM domains at the collision interface. Furthermore, we discover how this process is negatively reg

SUBMITTER: Huso VL 

PROVIDER: S-EPMC12823453 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature