Specific interaction of KIF11 with ZBP1 regulates the transport of beta-actin mRNA and cell motility

ZBP1-modulated localization of beta-actin mRNA enables a cell to establish polarity and structural asymmetry. Although the mechanism of beta-actin mRNA localization has been well established, the underlying mechanism of how a specific molecular motor contributes to the transport of the ZBP1 (also known as IGF2BP1) complex in non-neuronal cells remains elusive. In this study, we report the isolation and identification of KIF11, a microtubule motor, which physically interacts with ZBP1 and is a component of beta-actin messenger ribonucleoprotein particles (mRNPs). We show that KIF11 colocalizes with the beta-actin mRNA, and the ability of KIF11 to transport beta-actin mRNA is dependent on ZBP1. We characterize the corresponding regions of ZBP1 and KIF11 that mediate the interaction of the two proteins in vitro and in vivo. Disruption of the in vivo interaction of KIF11 with ZBP1 delocalizes beta-actin mRNA and affects cell migration. Our study reveals a molecular mechanism by which a particular microtubule motor mediates the transport of an mRNP through direct interaction with an mRNA-binding protein.