MOZART1 and ?-tubulin complex receptors are both required to turn ?-TuSC into an active microtubule nucleation template.

ABSTRACT: MOZART1/Mzt1 is required for the localization of ?-tubulin complexes to microtubule (MT)-organizing centers from yeast to human cells. Nevertheless, the molecular function of MOZART1/Mzt1 is largely unknown. Taking advantage of the minimal MT nucleation system of Candida albicans, we reconstituted the interactions of Mzt1, ?-tubulin small complex (?-TuSC), and ?-tubulin complex receptors (?-TuCRs) Spc72 and Spc110 in vitro. With affinity measurements, domain deletion, and swapping, we show that Spc110 and Mzt1 bind to distinct regions of the ?-TuSC. In contrast, both Mzt1 and ?-TuSC interact with the conserved CM1 motif of Spc110/Spc72. Spc110/Spc72 and Mzt1 constitute "oligomerization chaperones," cooperatively promoting and directing ?-TuSC oligomerization into MT nucleation-competent rings. Consistent with the functions of Mzt1, human MOZART1 directly interacts with the CM1-containing region of the ?-TuCR CEP215. MOZART1 depletion in human cells destabilizes the large ?-tubulin ring complex and abolishes CEP215^CM1-induced ectopic MT nucleation. Together, we reveal conserved functions of MOZART1/Mzt1 through interactions with ?-tubulin complex subunits and ?-TuCRs.

SUBMITTER: Lin TC 

PROVIDER: S-EPMC5166503 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature