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Inducible and Reversible Dominant-negative (DN) Protein Inhibition
08:35

Inducible and Reversible Dominant-negative (DN) Protein Inhibition

Published on: January 7, 2019

A dominant negative mutant of PMA1 interferes with the folding of the wild type enzyme

Pilar Eraso1, María J Mazón, Francisco Portillo

  • 1Departamento de Bioquímica and Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Arturo Duperier, 4, 28029 Madrid, Spain.

Traffic (Copenhagen, Denmark)
|November 26, 2009
PubMed

Insights

Dominant lethal PMA1 mutants cause yeast growth inhibition by retaining wild-type proteins in the endoplasmic reticulum (ER) for degradation. Deleting transmembrane helix 10 (TM10) suppresses this effect, revealing TM10

Area of Science:

  • Molecular biology
  • Cellular biology
  • Protein degradation

Background:

  • Misfolded proteins are typically degraded via ER-associated degradation (ERAD).
  • Mutant PMA1 alleles can cause misfolded proteins targeted for ERAD.
  • Some PMA1 mutants exhibit dominant negative effects, inhibiting yeast growth.

Purpose of the Study:

  • To investigate the mechanism of wild-type enzyme retention caused by dominant negative PMA1 mutants.
  • To identify genetic elements responsible for the dominant lethal phenotype of PMA1 mutants.

Main Methods:

  • Genetic screening for intragenic suppressors of the PMA1-D378T dominant lethal allele.
  • Analysis of transmembrane helix 10 (TM10) function in dominant lethality.
  • Biochemical assays to study protein folding and ER retention.

Main Results:

  • The PMA1-D378T dominant lethal allele's effect is linked to transmembrane helix 10 (TM10).
  • Deletion of TM10 suppressed all tested dominant lethal PMA1 alleles.
  • Biochemical data indicate TM10 in dominant lethal proteins interferes with wild-type enzyme folding, causing ER retention and ERAD.

Conclusions:

  • Transmembrane helix 10 is crucial for the dominant lethal phenotype of PMA1 mutants.
  • The dominant negative effect involves TM10-mediated obstruction of wild-type enzyme folding and subsequent ERAD.
  • Targeting TM10 could offer a strategy to overcome dominant negative protein interactions in yeast.

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