SNARE proteins are not excessive for the formation of post-Golgi SNARE complexes in HeLa cells

Miki Okayama, Akiko Shitara, Toshiya Arakawa, Yoshifumi Tajima, Itaru Mizoguchi, Taishin Takuma

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

To evaluate the role of SNARE proteins in the constitutive exocytosis, we knocked down syntaxin 3, 4, 5, 6, 7, and VAMP3, 5, 7, 8 with their siRNAs, and determined the cell-to-medium ratio of CLuc, a secreted luciferase of Cypridina noctiluca. Although the protein level of SNAREs in HeLa cells was markedly reduced by the siRNA treatment, the cell/medium ratio was scarcely increased by any siRNAs except for syntaxin 5. The accumulation of GFP-tagged human growth hormone was also visible only by the knockdown of syntaxin 5. To examine whether the residual amount of SNAREs are sufficient for maintaining normal constitutive exocytosis, we estimated the effect of siRNAs on the level of post-Golgi SNARE complexes containing syntaxin 4, SNAP23, and VAMP3 or VAMP8. The amount of SNARE complexes was robustly decreased by siRNAs and was well correlated with the residual amount of SNAREs in the lysates, suggesting that SNAREs are unnecessarily excessive for the formation of post-Golgi SNARE complexes in HeLa cells.

Original languageEnglish
Pages (from-to)159-168
Number of pages10
JournalMolecular and Cellular Biochemistry
Volume366
Issue number1-2
DOIs
Publication statusPublished - 2012 Jul 1
Externally publishedYes

Keywords

  • Constitutive secretion
  • Exocytosis
  • SNARE
  • SNARE complex
  • siRNA

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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