The catalytic subunit of DNA polymerase ? inhibits ?TuRC activity and regulates Golgi-derived microtubules.

ABSTRACT: ?-Tubulin ring complexes (?TuRCs) initiate microtubule growth and mediate microtubule attachment at microtubule-organizing centers, such as centrosomes and the Golgi complex. However, the mechanisms that control ?TuRC-mediated microtubule nucleation have remained mostly unknown. Here, we show that the DNA polymerase ? catalytic subunit (PolD1) binds directly to ?TuRCs and potently inhibits ?TuRC-mediated microtubule nucleation. Whereas PolD1 depletion through RNA interference does not influence centrosome-based microtubule growth, the depletion augments microtubule nucleation at the Golgi complex. Conversely, PolD1 overexpression inhibits Golgi-based microtubule nucleation. Golgi-derived microtubules are required for the assembly and maintenance of the proper Golgi structure, and we found that alteration of PolD1 levels affects Golgi structural organization. Moreover, suppression of PolD1 expression impairs Golgi reassembly after nocodazole-induced disassembly and causes defects in Golgi reorientation and directional cell migration. Collectively, these results reveal a mechanism that controls noncentrosomal ?TuRC activity and regulates the organization of Golgi-derived microtubules.Microtubule organization requires ?-tubulin ring complexes (?TuRCs), but the mechanisms that control ?TuRC-mediated microtubule nucleation are unclear. Here the authors show that the DNA polymerase ? catalytic subunit controls noncentrosomal ?TuRC activity and regulates the organization of Golgi-derived microtubules.

SUBMITTER: Shen Y 

PROVIDER: S-EPMC5601897 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature