Fig. 6: Mechanistic model for modular assembly of the human γ-TuRC.
From: Modular assembly of the principal microtubule nucleator γ-TuRC
a The initial step of γ-TuRC assembly is the formation of the 6-spoked stable core consisting of GCP2-3-4-5-4-6, in which the MZT1-GCP3 module is stabilized via the GCP6 GRIP1-NTE. Coloring as indicated. b Assembly continues (yellow arrow) via successive addition of γ-TuSC units. In this expansion phase, γ-TuSC units are conformationally locked (schematic lock symbol) when neighboring γ-TuSC units associate to the assembly intermediates (lighter color). During this process, the γ-TuSC(13,14) unit can repeatedly associate and dissociate. It is repositioned as soon as the lumenal bridge has formed. c Expansion ends (green arrow) in-ring closure, where the γ-TuSC(1,2) unit is integrated, stabilizes terminally the γ-TuSC(13,14) unit and locks the fully assembled 14-spoked complex.
