| First Author | Keller D | Year | 2014 |
| Journal | J Cell Biol | Volume | 204 |
| Issue | 5 | Pages | 697-712 |
| PubMed ID | 24590172 | Mgi Jnum | J:212978 |
| Mgi Id | MGI:5582653 | Doi | 10.1083/jcb.201307049 |
| Citation | Keller D, et al. (2014) Mechanisms of HsSAS-6 assembly promoting centriole formation in human cells. J Cell Biol 204(5):697-712 |
| abstractText | SAS-6 proteins are thought to impart the ninefold symmetry of centrioles, but the mechanisms by which their assembly occurs within cells remain elusive. In this paper, we provide evidence that the N-terminal, coiled-coil, and C-terminal domains of HsSAS-6 are each required for procentriole formation in human cells. Moreover, the coiled coil is necessary and sufficient to mediate HsSAS-6 centrosomal targeting. High-resolution imaging reveals that GFP-tagged HsSAS-6 variants localize in a torus around the base of the parental centriole before S phase, perhaps indicative of an initial loading platform. Moreover, fluorescence recovery after photobleaching analysis demonstrates that HsSAS-6 is immobilized progressively at centrosomes during cell cycle progression. Using fluorescence correlation spectroscopy and three-dimensional stochastic optical reconstruction microscopy, we uncover that HsSAS-6 is present in the cytoplasm primarily as a homodimer and that its oligomerization into a ninefold symmetrical ring occurs at centrioles. Together, our findings lead us to propose a mechanism whereby HsSAS-6 homodimers are targeted to centrosomes where the local environment and high concentration of HsSAS-6 promote oligomerization, thus initiating procentriole formation. |
