A targeted siRNA screen to identify SNAREs required for constitutive secretion in mammalian cells

Traffic. 2010 Sep;11(9):1191-204. doi: 10.1111/j.1600-0854.2010.01087.x. Epub 2010 Jun 10.


The role of SNAREs in mammalian constitutive secretion remains poorly defined. To address this, we have developed a novel flow cytometry-based assay for measuring constitutive secretion and have performed a targeted SNARE and Sec1/Munc18 (SM) protein-specific siRNA screen (38 SNAREs, 4 SNARE-like proteins and 7 SM proteins). We have identified the endoplasmic reticulum (ER)/Golgi SNAREs syntaxin 5, syntaxin 17, syntaxin 18, GS27, SLT1, Sec20, Sec22b, Ykt6 and the SM protein Sly1, along with the post-Golgi SNAREs SNAP-29 and syntaxin 19, as being required for constitutive secretion. Depletion of SNAP-29 or syntaxin 19 causes a decrease in the number of fusion events at the cell surface and in SNAP-29-depleted cells causes an increase in the number of docked vesicles at the plasma membrane as determined by total internal reflection fluorescence (TIRF) microscopy. Analysis of syntaxin 19-interacting partners by mass spectrometry indicates that syntaxin 19 can form SNARE complexes with SNAP-23, SNAP-25, SNAP-29, VAMP3 and VAMP8, supporting its role in Golgi to plasma membrane transport or fusion. Surprisingly, we have failed to detect any requirement for a post-Golgi-specific R-SNARE in this process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Flow Cytometry / methods*
  • Humans
  • Protein Transport
  • Qa-SNARE Proteins / metabolism
  • RNA, Small Interfering* / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • SNARE Proteins / genetics
  • SNARE Proteins / metabolism*
  • Signal Transduction


  • Qa-SNARE Proteins
  • RNA, Small Interfering
  • SNARE Proteins