Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]

Background: The mitochondrial protein import complexes arose early in eukaryogenesis. Most of the components of the protein import pathways predate the last eukaryotic common ancestor. For example, the carrier-insertase TIM22 complex comprises the widely conserved Tim22 channel core. However, the au...

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Main Authors: Sergio A. Muñoz-Gómez, Shannon N. Snyder, Samantha J. Montoya, Jeremy G. Wideman
Format: Article
Language:English
Published: F1000 Research Ltd 2020-08-01
Series:F1000Research
Online Access:https://f1000research.com/articles/9-1060/v1
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author Sergio A. Muñoz-Gómez
Shannon N. Snyder
Samantha J. Montoya
Jeremy G. Wideman
author_facet Sergio A. Muñoz-Gómez
Shannon N. Snyder
Samantha J. Montoya
Jeremy G. Wideman
author_sort Sergio A. Muñoz-Gómez
collection DOAJ
description Background: The mitochondrial protein import complexes arose early in eukaryogenesis. Most of the components of the protein import pathways predate the last eukaryotic common ancestor. For example, the carrier-insertase TIM22 complex comprises the widely conserved Tim22 channel core. However, the auxiliary components of fungal and animal TIM22 complexes are exceptions to this ancient conservation. Methods: Using comparative genomics and phylogenetic approaches, we identified precisely when each TIM22 accretion occurred. Results: In animals, we demonstrate that Tim29 and Tim10b arose early in the holozoan lineage. Tim29 predates the metazoan lineage being present in the animal sister lineages, choanoflagellate and filastereans, whereas the erroneously named Tim10b arose from a duplication of Tim9 at the base of metazoans. In fungi, we show that Tim54 has representatives present in every holomycotan lineage including microsporidians and fonticulids, whereas Tim18 and Tim12 appeared much later in fungal evolution. Specifically, Tim18 and Tim12 arose from duplications of Sdh3 and Tim10, respectively, early in the Saccharomycotina. Surprisingly, we show that Tim54 is distantly related to AGK suggesting that AGK and Tim54 are extremely divergent orthologues and the origin of AGK/Tim54 interaction with Tim22 predates the divergence of animals and fungi. Conclusions: We argue that the evolutionary history of the TIM22 complex is best understood as the neutral structural divergence of an otherwise strongly functionally conserved protein complex. This view suggests that many of the differences in structure/subunit composition of multi-protein complexes are non-adaptive. Instead, most of the phylogenetic variation of functionally conserved molecular machines, which have been under stable selective pressures for vast phylogenetic spans, such as the TIM22 complex, is most likely the outcome of the interplay of random genetic drift and mutation pressure.
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spelling doaj.art-84cff106f5ec4a0aa323ceed29b5a3612022-12-21T22:56:43ZengF1000 Research LtdF1000Research2046-14022020-08-01910.12688/f1000research.25904.128588Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]Sergio A. Muñoz-Gómez0Shannon N. Snyder1Samantha J. Montoya2Jeremy G. Wideman3Biodesign Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USABiodesign Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USABiodesign Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USABiodesign Center for Mechanisms of Evolution, School of Life Sciences, Arizona State University, Tempe, AZ, 85287, USABackground: The mitochondrial protein import complexes arose early in eukaryogenesis. Most of the components of the protein import pathways predate the last eukaryotic common ancestor. For example, the carrier-insertase TIM22 complex comprises the widely conserved Tim22 channel core. However, the auxiliary components of fungal and animal TIM22 complexes are exceptions to this ancient conservation. Methods: Using comparative genomics and phylogenetic approaches, we identified precisely when each TIM22 accretion occurred. Results: In animals, we demonstrate that Tim29 and Tim10b arose early in the holozoan lineage. Tim29 predates the metazoan lineage being present in the animal sister lineages, choanoflagellate and filastereans, whereas the erroneously named Tim10b arose from a duplication of Tim9 at the base of metazoans. In fungi, we show that Tim54 has representatives present in every holomycotan lineage including microsporidians and fonticulids, whereas Tim18 and Tim12 appeared much later in fungal evolution. Specifically, Tim18 and Tim12 arose from duplications of Sdh3 and Tim10, respectively, early in the Saccharomycotina. Surprisingly, we show that Tim54 is distantly related to AGK suggesting that AGK and Tim54 are extremely divergent orthologues and the origin of AGK/Tim54 interaction with Tim22 predates the divergence of animals and fungi. Conclusions: We argue that the evolutionary history of the TIM22 complex is best understood as the neutral structural divergence of an otherwise strongly functionally conserved protein complex. This view suggests that many of the differences in structure/subunit composition of multi-protein complexes are non-adaptive. Instead, most of the phylogenetic variation of functionally conserved molecular machines, which have been under stable selective pressures for vast phylogenetic spans, such as the TIM22 complex, is most likely the outcome of the interplay of random genetic drift and mutation pressure.https://f1000research.com/articles/9-1060/v1
spellingShingle Sergio A. Muñoz-Gómez
Shannon N. Snyder
Samantha J. Montoya
Jeremy G. Wideman
Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]
F1000Research
title Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]
title_full Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]
title_fullStr Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]
title_full_unstemmed Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]
title_short Independent accretion of TIM22 complex subunits in the animal and fungal lineages [version 1; peer review: 2 approved]
title_sort independent accretion of tim22 complex subunits in the animal and fungal lineages version 1 peer review 2 approved
url https://f1000research.com/articles/9-1060/v1
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AT shannonnsnyder independentaccretionoftim22complexsubunitsintheanimalandfungallineagesversion1peerreview2approved
AT samanthajmontoya independentaccretionoftim22complexsubunitsintheanimalandfungallineagesversion1peerreview2approved
AT jeremygwideman independentaccretionoftim22complexsubunitsintheanimalandfungallineagesversion1peerreview2approved