Protein Synthesis and Degradation
Roles of polyamines in translationPolyamines are organic polycations that bind to a variety of cellular molecules, including nucleic acids. Within cells, polyamines contribute to both the efficiency and fidelity of protein synthesis. In addition to directly acting on the translation apparatus to stimulate protein synthesis, the polyamine spermidine serves as a precursor for the essential post-translational modification of the eukaryotic translation factor 5A (eIF5A), which is required for synthesis of proteins containing problematic amino acid sequence motifs, including polyproline tracts, and for termination of translation.
Evidence That Base-pairing Interaction between Intron and mRNA Leader Sequences Inhibits Initiation of HAC1 mRNA Translation in YeastBackground: Hac1 protein, encoded by a cytoplasmically spliced mRNA, activates the unfolded protein response to maintain cellular protein homeostasis and alleviate endoplasmic reticulum stress.Results: Under non-stress conditions, translation initiation on the HAC1 mRNA is repressed.Conclusion: Base-pairing interaction between the 5′ leader and intron represses translation initiation on the HAC1 mRNA.Significance: A unique mechanism of intron-mediated inhibition of ribosomal scanning.