The Functional Specialization of Exomer as a Cargo Adaptor During the Evolution of Fungi

Genetics: A Periodical Record of Investigations Bearing on Heredity and Variation

Carlos Anton^1¹  Javier Valdez Taubas^2² 

[1] Departamento de Microbiología y Genética, Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas-Universidad de Salamanca, 37007, Spain^1;Departamento de Química Biológica, Centro de Investigaciones en Química Biológica de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Argentina^2

关键词: evolution;    exomer;    intracellular traffic;    yeast;   

DOI  :  10.1534/genetics.118.300767

学科分类：医学（综合）

来源: Genetics Society of America

【 摘 要 】

Yeast exomer is a heterotetrameric complex that is assembled at the trans -Golgi network, which is required for the delivery of a distinct set of proteins to the plasma membrane using ChAPs (Chs5-Arf1 binding proteins) Chs6 and Bch2 as dedicated cargo adaptors. However, our results show a significant functional divergence between them, suggesting an evolutionary specialization among the ChAPs. Moreover, the characterization of exomer mutants in several fungi indicates that exomer’s function as a cargo adaptor is a late evolutionary acquisition associated with several gene duplications of the fungal ChAPs ancestor. Initial gene duplication led to the formation of the two ChAPs families, Chs6 and Bch1, in the Saccaromycotina group, which have remained functionally redundant based on the characterization of Kluyveromyces lactis mutants. The whole-genome duplication that occurred within the Saccharomyces genus facilitated a further divergence, which allowed Chs6/Bch2 and Bch1/Bud7 pairs to become specialized for specific cellular functions. We also show that the behavior of S. cerevisiae Chs3 as an exomer cargo is associated with the presence of specific cytosolic domains in this protein, which favor its interaction with exomer and AP-1 complexes. However, these domains are not conserved in the Chs3 proteins of other fungi, suggesting that they arose late in the evolution of fungi associated with the specialization of ChAPs as cargo adaptors.

【 授权许可】

CC BY