Scientists Discover the First Protein That Can Edit Other Proteins

Links: http://www.wired.com/2015/01/grawk-proteins-making-proteins/

Scientists Discover the First Protein That Can Edit Other Proteins
Nick Stockton
1 January 2015

As we learned during our last unit, protein synthesis occurs in ribosomes and is coded for by mRNA. This, however, may not be the only way for proteins to be formed. Recently, scientists have discovered that some specific types of proteins can actually create new polypeptide sequences, without the use of mRNA. One such protein is Rqc2. Rqc2 is a protein involved in a recycling process that takes place when an error happens in translation. When such an error occurs, the ribosome essentially stalls and is unusable, until a group of proteins come in and break apart the ribsome, mRNA, and the partially made protein. Rqc2's role in this clean-up process is to attach a random sequence of the amino acids threonine and alanine to the partially made protein before it is recycled. This newly added sequence will not fix the ribosome, or complete the protein. It will instead act as a signal to other destructive proteins to take the faulty one apart. What is surprising about this process is that a protein, not mRNA, decides which amino acids will be added.
 Diseases such as Alzheimer's, Huntington's, and Lou Gehrig's are caused by defective quality control proteins. Knowing the exact conditions that trigger Rqc2 could help lead to new treatments for such
conditions.

This article directly relates to our last unit on molecular biology. Although the article describes a different process than we discussed in class, it is still about protein synthesis, which was an important part of our last topic.