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Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation
14:44

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Published on: March 14, 2014

A novel transport pathway for a yeast plasma membrane protein encoded by a localized mRNA

Christoph Jüschke1, Dunja Ferring, Ralf-Peter Jansen

  • 1Center of Molecular Biology at University of Heidelberg (ZMBH), Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.

Current Biology : CB
|March 19, 2004
PubMed

Insights

Localized IST2 mRNA ensures Ist2p delivery to the plasma membrane in yeast daughter cells. This protein trafficking bypasses the standard secretory pathway, suggesting a novel ER-to-plasma membrane route.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Yeast Genetics

Background:

  • Plasma membrane proteins typically enter the secretory pathway via the endoplasmic reticulum.
  • The yeast protein Ist2p is encoded by mRNA localized to daughter cell cortices, suggesting localized translation.
  • This localization implies Ist2p might be specifically translated at the cortical endoplasmic reticulum.

Purpose of the Study:

  • To investigate the role of IST2 mRNA localization in Ist2p delivery to the plasma membrane.
  • To determine if Ist2p follows the canonical secretory pathway or a novel trafficking route.
  • To elucidate the mechanism of Ist2p transport to the plasma membrane in yeast daughter cells.

Main Methods:

  • mRNA localization studies using constitutively expressed IST2.
  • Analysis of Ist2p trafficking in wild-type and secretory pathway mutant yeast strains.
  • Colocalization experiments to track protein transport.
  • Comparison with the trafficking of a canonical plasma membrane protein, Hxt1p.

Main Results:

  • IST2 mRNA localization is essential for Ist2p delivery to the plasma membrane of daughter cells, but not mother cells.
  • Ist2p accumulation is not specific to daughter cells despite mRNA localization.
  • Ist2p trafficking is independent of myosin-mediated vesicular transport and the classical secretory pathway machinery.

Conclusions:

  • Yeast mRNA localization directs protein delivery to specific cellular compartments.
  • Ist2p utilizes a non-canonical pathway for transport from the endoplasmic reticulum to the plasma membrane.
  • A novel ER-to-plasma membrane trafficking route distinct from the Golgi-dependent secretory pathway exists.

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