Scientists at the Princess Maxima Center for Pediatric Oncology in the Netherlands have discovered thousands of previously unknown microproteins in human organs. This is reported in an article published in the journal Molecular Cell .
Unlike known old proteins that were long coded in the genome, most microproteins arose from regions of DNA that were non-coding, that is, not involved in the production of proteins. Because these small proteins only appeared during human evolution, they are absent from the cells of most other animals, such as mice, fish, and birds. However, these animals have been found to possess their own collection of evolutionarily young small proteins.
The researchers also discovered the smallest human proteins identified to date. More than 200 ultra-small proteins have been identified, each less than 16 amino acids in size. These molecules can bind to larger proteins, affecting cell function, but it remains unclear whether they play the role of hormones or perform some other function.
Based on additional cellular analyzes, the researchers linked several candidates to messenger RNA splicing, translational regulation, and endocytosis. The results of the study provide insight into the evolutionary origins and interaction potential of evolutionarily young and small proteins, thereby helping to explore a little-known area of the human proteome.