Evolutionary cell biology traces the rise of the exomer complex in Fungi from an ancient eukaryotic component

Sci Rep. 2018 Jul 24;8(1):11154. doi: 10.1038/s41598-018-29416-4.

Abstract

Cargo is transported from the trans-Golgi Network to the plasma membrane by adaptor complexes, which are pan-eukaryotic components. However, in yeast, cargo can also be exported by the exomer complex, a heterotetrameric protein complex consisting of two copies of Chs5, and any two members of four paralogous proteins (ChAPs). To understand the larger relevance of exomer, its phylogenetic distribution and function outside of yeast need to be explored. We find that the four ChAP proteins are derived from gene duplications after the divergence of Yarrowia from the remaining Saccharomycotina, with BC8 paralogues (Bch2 and Chs6) being more diverged relative to the BB8 paralogues (Bch1 and Bud7), suggesting neofunctionalization. Outside Ascomycota, a single preduplicate ChAP is present in nearly all Fungi and in diverse eukaryotes, but has been repeatedly lost. Chs5, however, is a fungal specific feature, appearing coincidentally with the loss of AP-4. In contrast, the ChAP protein is a wide-spread, yet uncharacterized, membrane-trafficking component, adding one more piece to the increasingly complex machinery deduced as being present in our ancient eukaryotic ancestor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / metabolism
  • Biological Evolution*
  • Cell Biology*
  • Cell Membrane / metabolism
  • Chitin Synthase / genetics
  • Chitin Synthase / metabolism
  • Eukaryotic Cells / metabolism*
  • Galactokinase / metabolism
  • Gene Duplication
  • Golgi Apparatus / metabolism*
  • Microscopy, Fluorescence
  • Phenotype
  • Phylogeny*
  • Protein Binding
  • Protein Transport
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sequence Homology
  • trans-Golgi Network / metabolism*

Substances

  • Adaptor Proteins, Vesicular Transport
  • Saccharomyces cerevisiae Proteins
  • CHS5 protein, S cerevisiae
  • Chitin Synthase
  • GAL1 protein, S cerevisiae
  • Galactokinase