New factors for protein transport identified by a genome-wide CRISPRi screen in mammalian cells

J Cell Biol. 2019 Nov 4;218(11):3861-3879. doi: 10.1083/jcb.201902028. Epub 2019 Sep 5.


Protein and membrane trafficking pathways are critical for cell and tissue homeostasis. Traditional genetic and biochemical approaches have shed light on basic principles underlying these processes. However, the list of factors required for secretory pathway function remains incomplete, and mechanisms involved in their adaptation poorly understood. Here, we present a powerful strategy based on a pooled genome-wide CRISPRi screen that allowed the identification of new factors involved in protein transport. Two newly identified factors, TTC17 and CCDC157, localized along the secretory pathway and were found to interact with resident proteins of ER-Golgi membranes. In addition, we uncovered that upon TTC17 knockdown, the polarized organization of Golgi cisternae was altered, creating glycosylation defects, and that CCDC157 is an important factor for the fusion of transport carriers to Golgi membranes. In conclusion, our work identified and characterized new actors in the mechanisms of protein transport and secretion and opens stimulating perspectives for the use of our platform in physiological and pathological contexts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cells, Cultured
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics*
  • Golgi Apparatus / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans


  • Carrier Proteins
  • Cell Cycle Proteins
  • tetratricopeptide repeat protein 17, human