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. 2020 Aug 28;9:1060. [Version 1] doi: 10.12688/f1000research.25904.1

Figure 4. TIM22 complex subunits were gained independently in the animal and fungal lineages.

Figure 4.

The ancestral TIM22 complex comprises a single subunit, Tim22, which likely interacted with the small Tims, Tim9 and Tim10. The ancestral opisthokont TIM22 complex contained an additional subunit, AGK, which retains a diacylglycerol kinase (DAGK) domain in holozoans. In the holomycotan lineage, the DAGK domain was lost or diverged beyond recognition, but stabilized into Tim54, which is well-conserved across Holomycota. Early in the evolution of Saccharomycotina, Tim12 was gained via a duplication of Tim10, and Tim18 was gained via a duplication of Sdh4. Shortly after the divergence of Holozoa from Holomycota, Tim29 was gained as a subunit of the TIM22 complex. Tim10b was gained after the divergence of Metazoa from the unicellular holozoans from a duplication of Tim9. Tim8a and Tim8b result from a duplication of Tim8 in the lineage leading to chordates (not shown).