10.1371/journal.pgen.1004034.g009 Figure 9  Proposed model of CIII assembly.
Complex III assembly begins with the translation activation and/or stabilization of cytochrome b (MTCYB) by UQCC1:UQCC2, which then delivers MTCYB to an assembly intermediate containing UQCRQ and UQCRB. This module combines with a module containing CYC1, UQCRH and UQCR10 and a module containing UQCRC2 and UQCRC1. The resulting subcomplex then dimerizes. UQCRFS1 is bound and stabilized by the CIII assembly factor LYRM7, before being incorporated into CIII with the aid of the assembly factor, BCS1L. Finally UQCR11 is added, forming the complete CIII2. Assembly factors are indicated in gray. Proteins in which mutations are associated with complex III deficiency are bordered in red. The role of TTC19 is yet to be elucidated, although it is likely to be involved in early complex III assembly. Model adapted and updated from [67].