6YS4

Structure of the Homo sapiens SAS-6 coiled-coil domain

Summary for 6YS4

• Entry DOI: 10.2210/pdb6ys4/pdb
• Descriptor: Spindle assembly abnormal protein 6 homolog, TETRAETHYLENE GLYCOL, GLYCINE, ... (4 entities in total)
• Functional Keywords: centriole, centrosome, cartwheel, coiled coil, complex, alpha helical, structural protein
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 6
• Total formula weight: 74356.38

Authors

Kantsadi, A.L.,Vakonakis, I. (deposition date: 2020-04-21, release date: 2021-05-12, Last modification date: 2024-11-06)

Primary citation

Kantsadi, A.L.,Hatzopoulos, G.N.,Gonczy, P.,Vakonakis, I.
Structures of SAS-6 coiled coil hold implications for the polarity of the centriolar cartwheel.
Structure, 2022

PubMed Abstract: Centrioles are eukaryotic organelles that template the formation of cilia and flagella, as well as organize the microtubule network and the mitotic spindle in animal cells. Centrioles have proximal-distal polarity and a 9-fold radial symmetry imparted by a likewise symmetrical central scaffold, the cartwheel. The spindle assembly abnormal protein 6 (SAS-6) self-assembles into 9-fold radially symmetric ring-shaped oligomers that stack via an unknown mechanism to form the cartwheel. Here, we uncover a homo-oligomerization interaction mediated by the coiled-coil domain of SAS-6. Crystallographic structures of Chlamydomonas reinhardtii SAS-6 coiled-coil complexes suggest this interaction is asymmetric, thereby imparting polarity to the cartwheel. Using a cryoelectron microscopy (cryo-EM) reconstitution assay, we demonstrate that amino acid substitutions disrupting this asymmetric association also impair SAS-6 ring stacking. Our work raises the possibility that the asymmetric interaction inherent to SAS-6 coiled-coil provides a polar element for cartwheel assembly, which may assist the establishment of the centriolar proximal-distal axis.

PubMed: 35240058
DOI: 10.1016/j.str.2022.02.005

Experimental method

X-RAY DIFFRACTION (2.11 Å)