Biomedical subjects

Robert Gauss

Publications and source records attributed to Robert Gauss.

5 recordsLinked to original sources

PubMed2006

Coping with stress: cellular relaxation techniques.

Proteins damaged by stressors such as heat, oxidizing conditions or toxic agents are deleterious to cells and must be properly taken care of. Accordingly, misfolded proteins trigger a cellular stress response that aims to either repair defective polypeptides or eliminate faulty elements when salvage is not possible. This stress response provides time for additional stressor-specific pathways that adapt the cell to the changed environment if necessary. Recent studies have investigated how proteins that frustrate the folding machinery are recognized and cleared from the cell. Surprisingly, these clearance mechanisms are not restricted to the protein level. The stress response can also eliminate the mRNA of polypeptides that are refractory to folding.

Animals↗

PubMed2006

A complex of Yos9p and the HRD ligase integrates endoplasmic reticulum quality control into the degradation machinery.

A quality-control system surveys the lumen of the endoplasmic reticulum for terminally misfolded proteins. Polypeptides singled out by this system are ultimately degraded by the cytosolic ubiquitin-proteasome pathway. Key components of both the endoplasmic reticulum quality-control system and the degradation machinery have been identified, but a connection between the two systems has remained elusive. Here, we report an association between the endoplasmic reticulum quality-control lectin Yos9p and Hrd3p, a component of the ubiquitin-proteasome system that links these pathways. We identify designated regions in the luminal domain of Hrd3p that interact with Yos9p and the ubiquitin ligase Hrd1p. Binding of misfolded proteins occurs through Hrd3p, suggesting that Hrd3p recognises proteins that deviate from their native conformation, whereas Yos9p ensures that only terminally misfolded polypeptides are degraded.

Blotting, Western↗

PubMed2006

The Hrd1p ligase complex forms a linchpin between ER-lumenal substrate selection and Cdc48p recruitment.

Misfolded proteins of the endoplasmic reticulum (ER) are targeted to the cytoplasm for proteasomal degradation. Key components of this process are ER membrane-bound ubiquitin ligases. These ligases associate with the cytoplasmic AAA-ATPase Cdc48p/p97, which is thought to support the release of malfolded proteins from the ER. Here, we characterize a yeast protein complex containing the ubiquitin ligase Hrd1p and the ER membrane proteins Hrd3p and Der1p. Hrd3p binds malfolded proteins in the ER lumen enabling their delivery to downstream components. Therefore, we propose that Hrd3p acts as a substrate recruitment factor for the Hrd1p ligase complex. Hrd3p function is also required for the association of Cdc48p with Hrd1p. Moreover, our data demonstrate that recruitment of Cdc48p depends on substrate processing by the Hrd1p ligase complex. Thus, the Hrd1p ligase complex unites substrate selection in the ER lumen and polyubiquitination in the cytoplasm and links these processes to the release of ER proteins via the Cdc48p complex.

Adenosine Triphosphatases↗

PubMed2006

Arf1p, Chs5p and the ChAPs are required for export of specialized cargo from the Golgi.

In Saccharomyces cerevisiae, the synthesis of chitin is temporally and spatially regulated through the transport of Chs3p (chitin synthase III) to the plasma membrane in the bud neck region. Traffic of Chs3p from the trans-Golgi network (TGN)/early endosome to the plasma membrane requires the function of Chs5p and Chs6p. Chs6p belongs to a family of four proteins that we have named ChAPs for Chs5p-Arf1p-binding Proteins. Here, we show that all ChAPs physically interact not only with Chs5p but also with the small GTPase Arf1p. A short sequence at the C-terminus of the ChAPs is required for protein function and the ability to bind to Chs5p. Simultaneous disruption of two members, Deltabud7 and Deltabch1, phenocopies a Deltachs6 or Deltachs5 deletion with respect to Chs3p transport. Moreover, the ChAPs interact with each other and can form complexes. In addition, they are all at least partially localized to the TGN in a Chs5p-dependent manner. Most importantly, several ChAPs can interact physically with Chs3p. We propose that the ChAPs facilitate export of cargo out of the Golgi.

ADP-Ribosylation Factor 1↗

PubMed2005

New modules for the repeated internal and N-terminal epitope tagging of genes in Saccharomyces cerevisiae.

Epitope tagging is a powerful method for the rapid analysis of protein function. In Saccharomyces cerevisiae epitope tags are introduced easily into chromosomal loci by homologous recombination using a simple PCR-based strategy. Although quite a number of tools exist for C-terminal tagging as well as N-terminal tagging of proteins expressed by heterologous promoters, there are only very limited possibilities to tag proteins at the N-terminus and retain the endogenous expression level. Furthermore, no PCR-templates for internal tagging have been reported. Here we describe new modules that are suitable for both the repeated N-terminal and internal tagging of proteins, leaving their endogenous promoters intact. The tags include 6xHA, 9xMyc, yEGFP, TEV-GST-6xHIS, ProtA, TEV-ProtA and TEV-ProtA-7xHIS in conjunction with different heterologous selection markers.

Amino Acid Sequence↗