title: Differential Stoichiometry among Core Ribosomal Proteins.
abstract: Understanding the regulation and structure of ribosomes is essential to understanding protein synthesis and its dysregulation in disease. While ribosomes are believed to have a fixed stoichiometry among their core ribosomal proteins (RPs), some experiments suggest a more variable composition. Testing such variability requires direct and precise quantification of RPs. We used mass spectrometry to directly quantify RPs across monosomes and polysomes of mouse embryonic stem cells (ESC) and budding yeast. Our data show that the stoichiometry among core RPs in wild-type yeast cells and ESC depends both on the growth conditions and on the number of ribosomes bound per mRNA. Furthermore, we find that the fitness of cells with a deleted RP-gene is inversely proportional to the enrichment of the corresponding RP in polysomes. Together, our findings support the existence of ribosomes with distinct protein composition and physiological function.
authors.affiliation: Department of Bioengineering, Northeastern University, Boston, MA 02115, USA; Department of Statistics and FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA. Electronic address: nslavov@alum.mit.edu.
authors.forename: Nikolai
authors.initials: N
authors.lastname: Slavov
authors.affiliation: Leiden Institute of Physics, Leiden University, 2333 CC Leiden, the Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Semrau
authors.affiliation: Department of Statistics and FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Airoldi
authors.affiliation: Department of Statistics and FAS Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Budnik
authors.affiliation: Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, Uppsalalaan 8, 3584 CT Utrecht, the Netherlands.
authors.forename: Alexander
authors.initials: A
authors.lastname: van Oudenaarden
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D012269:Ribosomal Proteins / Q000737:chemistry* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins