Kinesin molecular motor Eg5 functions during polypeptide synthesis
The microtubule motor Eg5 is well known for its functions during mitosis. It is shown that during interphase, Eg5 associates with ribosomes and is required for efficient protein synthesis.The kinesin-related molecular motor Eg5 plays roles in cell division, promoting spindle assembly. We show that during interphase Eg5 is associated with ribosomes and is required for optimal nascent polypeptide synthesis. When Eg5 was inhibited, ribosomes no longer bound to microtubules in vitro, ribosome transit rates slowed, and polysomes accumulated in intact cells, suggesting defects in elongation or termination during polypeptide synthesis. These results demonstrate that the molecular motor Eg5 associates with ribosomes and enhances the efficiency of translation.