9. 7. 2026
An international team of scientists has described a previously overlooked mechanism that regulates the levels of important proteins in human cells. A new study published in Nucleic Acids Research reveals that short regulatory “start–stop“ elements act as highly effective speed-limiting gates of protein synthesis. Compared with previously known regulatory sequences, these elements were found to suppress protein production even more efficiently. At the same time, they help maintain low but stable levels of important proteins in cells, even under stress conditions. The study brought together scientists from the United States, the Czech Republic, Canada, and Sweden. Leoš Shivaya Valášek, Head of the Laboratory of Regulation of Gene Expression at the Institute of Microbiology of the Czech Academy of Sciences (IMIC CAS) was a co-author and one of the corresponding authors of the study.
During protein production, ribosomes read and translate information encoded in messenger RNA (mRNA) into amino acids, which are then assembled into a new protein. The researchers focused on an unusual sequence in which a start signal is immediately followed by a stop signal. As a result, the ribosome receives instructions to begin and terminate translation almost simultaneously. Although such an arrangement may appear illogical, it proved to be an important regulatory tool.
Start–stop motifs are found in more than 1,400 human genes and are particularly common in genes that control cellular signaling pathways, the stress response, or the activity of transcription factors—that is, proteins that regulate the activity of other genes. These genes must be tightly controlled because even small changes in the amount of their protein products can have significant biological consequences.
Resilience Under Stress
The researchers tested the activity of this regulatory mechanism under stress conditions, including in the ATF4 gene, which plays a key role in the so-called integrated stress response. Cellular stress is typically associated with a global reduction in protein synthesis. The authors demonstrated that regulation mediated by start-stop elements is largely independent of the overall state of translation initiation and therefore remains effective even under cellular stress.
A Stronger Brake Than Known Regulatory Elements
The team compared start–stop sequences with similar regulatory regions known as uTranslons. Although both types of elements suppress protein synthesis, the start–stop sequences proved to be significantly more effective. Ribosomes remain associated with these motives for longer before proceeding to the main coding region of the gene.
“Start-stop sequences are specialized regulatory elements that ensure increased ribosome retention, thereby allowing for fine-tuning translation,” says Leoš Valášek from IMIC CAS.
The study expands our understanding of how cells fine-tune protein synthesis and may ultimately contribute to research on certain cancer and neurodegenerative disorders, and other diseases linked to disrupted protein production.
PUBLICATION: Justin Rendleman et al., Elongationless start–stop elements are stress-resilient translation gates that are more repressive than uTranslons. Nucleic Acids Research (2026), Volume 54, Issue 13, https://doi.org/10.1093/nar/gkag627
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