Translation dynamics in human cells visualized at high resolution reveal cancer drug action

Ribosomes catalyze protein synthesis by cycling through various functional states. These states have been extensively characterized in vitro, but their distribution in actively translating human cells remains elusive. We used a cryo-electron tomography-based approach and resolved ribosome structures inside human cells with high resolution. These structures revealed the distribution of functional states of the elongation cycle, a Z transfer RNA binding site, and the dynamics of ribosome expansion segments. Ribosome structures from cells treated with Homoharringtonine, a drug used against chronic myeloid leukemia, revealed how translation dynamics were altered in situ and resolve the small molecules within the active site of the ribosome. Thus, structural dynamics and drug effects can be assessed at high resolution within human cells.

Automated summary

Using cryo-electron tomography, we resolved high-resolution ribosome structures inside human cells, revealing their distribution of functional states, including the elongation cycle, Z transfer RNA binding site, and ribosome expansion segments dynamics. Studying ribosome structures from cells treated with Homoharringtonine, a drug used against chronic myeloid leukemia, we discovered how translation dynamics were altered in situ and identified small molecules within the active site of the ribosome. Thus, we can assess structural dynamics and drug effects at high resolution within human cells.