The obligate intracellular bacterial pathogen Chlamydia trachomatis deploys virulence effectors to subvert host cell functions enabling its replication within a specialized membrane-bound compartment termed an inclusion. The control of the host cytoskeleton is critical for Chlamydia uptake, inclusion biogenesis and cell exit. Here we demonstrate how a Chlamydia effector rearranges the microtubule network by initiating organization of the microtubules at the inclusion surface. We identified an inclusion-localized effector sufficient to interfere with microtubule assembly that we term inclusion protein acting on microtubules (IPAM). We established that IPAM recruits and stimulates the centrosomal protein 170kDa (CEP170) to hijack the microtubule organizing functions of the host cell. We show that CEP170 is essential for chlamydial control of host microtubule assembly, and is required for inclusion morphogenesis and bacterial infectivity. Together, we demonstrate how a pathogen effector reprograms the host microtubule network to support its intracellular development
