Yeast Vps13 is Crucial for Peroxisome Expansion in Cells With Reduced Peroxisome-ER Contact Sites.

In the yeast the peroxisomal membrane protein Pex11 and three endoplasmic reticulum localized proteins of the Pex23 family (Pex23, Pex24 and Pex32) are involved in the formation of peroxisome-ER contact sites. Previous studies suggested that these contacts are involved in non-vesicular lipid transfer and important for expansion of the peroxisomal membrane. The absence of Pex32 results in a severe peroxisomal phenotype, while cells lacking Pex11, Pex23 or Pex24 show milder defects and still are capable to form peroxisomes and grow on methanol.

Pex24 and Pex32 are required to tether peroxisomes to the ER for organelle biogenesis, positioning and segregation in yeast.

The yeast contains four members of the Pex23 family of peroxins, which characteristically contain a DysF domain. Here we show that all four Pex23 family proteins localize to the endoplasmic reticulum (ER). Pex24 and Pex32, but not Pex23 and Pex29, predominantly accumulate at peroxisome-ER contacts.

Age-dependent deterioration of nuclear pore assembly in mitotic cells decreases transport dynamics.

Nuclear transport is facilitated by the Nuclear Pore Complex (NPC) and is essential for life in eukaryotes. The NPC is a long-lived and exceptionally large structure. We asked whether NPC quality control is compromised in aging mitotic cells.

Peroxisome development in yeast is associated with the formation of Pex3-dependent peroxisome-vacuole contact sites.

Using electron and fluorescence microscopy techniques, we identified various physical contacts between peroxisomes and other cell organelles in the yeast Hansenula polymorpha. In exponential glucose-grown cells, which typically contain a single small peroxisome, contacts were only observed with the endoplasmic reticulum and the plasma membrane. Here we focus on a novel peroxisome-vacuole contact site that is formed when glucose-grown cells are shifted to methanol containing media, conditions that induce strong peroxisome development.

Yeast peroxisomes: How are they formed and how do they grow?

Peroxisomes are single membrane enclosed cell organelles, which are present in almost all eukaryotic cells. In addition to the common peroxisomal pathways such as β-oxidation of fatty acids and decomposition of HO, these organelles fulfil a range of metabolic and non-metabolic functions. Peroxisomes are very important since various human disorders exist that are caused by a defect in peroxisome function.

In vivo evolutionary engineering for ethanol-tolerance of Saccharomyces cerevisiae haploid cells triggers diploidization.

Microbial ethanol production is an important alternative energy resource to replace fossil fuels, but at high level, this product is highly toxic, which hampers its efficient production. Towards increasing ethanol-tolerance of Saccharomyces cerevisiae, the so far best industrial ethanol-producer, we evaluated an in vivo evolutionary engineering strategy based on batch selection under both constant (5%, v v) and gradually increasing (5-11.4%, v v) ethanol concentrations.