Correct. There are lots of potential reasons why protein and mRNA levels don’t agree with one another. There is regulation at every stage in the pathway including protein stability and turnover. Also remember this when interpreting RNAseq or other mRNA abundance data.
mRNA degradation is as tightly controlled as production. It is just as important to turn off a signal at the right time as to turn it on. The best-studied regulatory elements controlling mRNA stability are known as AU-rich elements (AURE). These are found in the 3′ UTR region of many genes that need to have short half-life mRNAs. From this information, can you predict which of the following classes of protein-coding genes are likely to be controlled by AURE?
LaNts and Laminins 