Arginyltransferase1 drives a mitochondria-dependent program to induce cell death.

Cell death regulation is essential for stress adaptation and/or signal response. Past studies have shown that eukaryotic cell death is mediated by an evolutionarily conserved enzyme, arginyltransferase1 (Ate1). The downregulation of Ate1, as seen in many types of cancer, prominently increases cellular tolerance to a variety of stress conditions.

Arginyltransferase1 drives a mitochondria-dependent program to induce cell death.

Cell death regulation is essential for stress adaptation and/or signal response. Past studies have shown that eukaryotic cell death is mediated by an evolutionarily conserved enzyme, arginyltransferase1 (Ate1). The downregulation of Ate1, as seen in many types of cancer, prominently increases cellular tolerance to a variety of stressing conditions.

Ribosome-associated quality control mediates degradation of the premature translation termination product Orf1p of ODC antizyme mRNA.

Decoding of OAZ1 (Ornithine decarboxylase AntiZyme 1) mRNA, which harbours two open reading frames (ORF1 and ORF2) interrupted by a naturally occurring Premature Termination Codon (PTC), produces an 8 kDa truncated polypeptide termed Orf1p, unless the PTC is bypassed by +1 ribosomal frameshifting. In this study, we identified Orf1p as an endogenous ubiquitin-dependent substrate of the 26S proteasome both in yeast and mammalian cells. Surprisingly, we found that the ribosome-associated quality control factor Rqc1 and the ubiquitin ligase Ltn1 are critical for Orf1p degradation.

Ccr4-Not complex subunits Ccr4, Caf1, and Not4 are novel proteolysis factors promoting the degradation of ubiquitin-dependent substrates by the 26S proteasome.

Degradation of short-lived and abnormal proteins is essential for normal cellular homeostasis. In eukaryotes, such unstable cellular proteins are selectively degraded by the ubiquitin proteasome system (UPS). Abnormalities in protein degradation by the UPS have been linked to several human diseases.

Hsp70-Hsp110 chaperones deliver ubiquitin-dependent and -independent substrates to the 26S proteasome for proteolysis in yeast.

During protein quality control, proteotoxic misfolded proteins are recognized by molecular chaperones, ubiquitylated by dedicated quality control ligases and delivered to the 26S proteasome for degradation. Proteins belonging to the Hsp70 chaperone and Hsp110 (the Hsp70 nucleotide exchange factor) families function in the degradation of misfolded proteins by the ubiquitin-proteasome system via poorly understood mechanisms. Here, we report that the Hsp110 proteins (Sse1 and Sse2) function in the degradation of Hsp70-associated ubiquitin conjugates at the post-ubiquitylation step and are also required for ubiquitin-independent proteasomal degradation.

Coordinated Hsp110 and Hsp104 Activities Power Protein Disaggregation in Saccharomyces cerevisiae.

Protein aggregation is intimately associated with cellular stress and is accelerated during aging, disease, and cellular dysfunction. Yeast cells rely on the ATP-consuming chaperone Hsp104 to disaggregate proteins together with Hsp70. Hsp110s are ancient and abundant chaperones that form complexes with Hsp70.

Luciferase NanoLuc as a reporter for gene expression and protein levels in Saccharomyces cerevisiae.

Reporter proteins are essential tools in the study of biological processes and are employed to monitor changes in gene expression and protein levels. Luciferases are reporter proteins that enable rapid and highly sensitive detection with an outstanding dynamic range. Here we evaluated the usefulness of the 19 kDa luciferase NanoLuc (Nluc), derived from the deep sea shrimp Oplophorus gracilirostris, as a reporter protein in yeast.

Hsp70 nucleotide exchange factor Fes1 is essential for ubiquitin-dependent degradation of misfolded cytosolic proteins.

Protein quality control systems protect cells against the accumulation of toxic misfolded proteins by promoting their selective degradation. Malfunctions of quality control systems are linked to aging and neurodegenerative disease. Folding of polypeptides is facilitated by the association of 70 kDa Heat shock protein (Hsp70) molecular chaperones.