Interrogation of Mammalian Protein Complex Structure, Function, and Membership Using Genome-Scale Fitness Screens

Cell Syst. 2018 May 23;6(5):555-568.e7. doi: 10.1016/j.cels.2018.04.011. Epub 2018 May 16.


Protein complexes are assemblies of subunits that have co-evolved to execute one or many coordinated functions in the cellular environment. Functional annotation of mammalian protein complexes is critical to understanding biological processes, as well as disease mechanisms. Here, we used genetic co-essentiality derived from genome-scale RNAi- and CRISPR-Cas9-based fitness screens performed across hundreds of human cancer cell lines to assign measures of functional similarity. From these measures, we systematically built and characterized functional similarity networks that recapitulate known structural and functional features of well-studied protein complexes and resolve novel functional modules within complexes lacking structural resolution, such as the mammalian SWI/SNF complex. Finally, by integrating functional networks with large protein-protein interaction networks, we discovered novel protein complexes involving recently evolved genes of unknown function. Taken together, these findings demonstrate the utility of genetic perturbation screens alone, and in combination with large-scale biophysical data, to enhance our understanding of mammalian protein complexes in normal and disease states.

Keywords: fitness correlations; genetic perturbation screens; mammalian SWI/SNF; protein complexes; shRNA and CRISPR/Cas9-based genetic screens.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • A549 Cells
  • Animals
  • CRISPR-Cas Systems
  • Cell Line, Tumor
  • Genes, Essential / genetics
  • Genetic Fitness / genetics*
  • Genetic Testing / methods
  • HEK293 Cells
  • Humans
  • Mammals / genetics
  • Multiprotein Complexes / genetics
  • Protein Interaction Mapping / methods*
  • Protein Interaction Maps / genetics*
  • RNA Interference


  • Multiprotein Complexes

Associated data

  • figshare/10.6084/m9.figshare.6005297