title: Protein abundances are more conserved than mRNA abundances across diverse taxa.
abstract: Proteins play major roles in most biological processes; as a consequence, protein expression levels are highly regulated. While extensive post-transcriptional, translational and protein degradation control clearly influence protein concentration and functionality, it is often thought that protein abundances are primarily determined by the abundances of the corresponding mRNAs. Hence surprisingly, a recent study showed that abundances of orthologous nematode and fly proteins correlate better than their corresponding mRNA abundances. We tested if this phenomenon is general by collecting and testing matching large-scale protein and mRNA expression data sets from seven different species: two bacteria, yeast, nematode, fly, human, and rice. We find that steady-state abundances of proteins show significantly higher correlation across these diverse phylogenetic taxa than the abundances of their corresponding mRNAs (p=0.0008, paired Wilcoxon). These data support the presence of strong selective pressure to maintain protein abundances during evolution, even when mRNA abundances diverge.
authors.affiliation: Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, University of Texas at Austin, TX, USA.
authors.forename: Jon M
authors.initials: JM
authors.lastname: Laurent
authors.forename: Christine
authors.initials: C
authors.lastname: Vogel
authors.forename: Taejoon
authors.initials: T
authors.lastname: Kwon
authors.forename: Stephanie A
authors.initials: SA
authors.lastname: Craig
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Boutz
authors.forename: Holly K
authors.initials: HK
authors.lastname: Huse
authors.forename: Kazunari
authors.initials: K
authors.lastname: Nozue
authors.forename: Harkamal
authors.initials: H
authors.lastname: Walia
authors.forename: Marvin
authors.initials: M
authors.lastname: Whiteley
authors.forename: Pamela C
authors.initials: PC
authors.lastname: Ronald
authors.forename: Edward M
authors.initials: EM
authors.lastname: Marcotte
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D029742:Caenorhabditis elegans Proteins; D029721:Drosophila Proteins; D010940:Plant Proteins; D011506:Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins