Perspective
Post-translational modification is an important way to regulate protein function. Different sites on a single protein allow for triggering varied functions of the same protein, depending on the cellular requirements and/or environmental stimuli. This allows for fine-tuning of the protein function. YBX1 has emerged as one of the proteins substantially post-translationally modified, as identified by advanced mass spectrometric proteomics (Table 1 and Table 2). This vast amount of information makes post-translational modification of YBX1 an exciting research area for further exploration.
Based on the fact that many post-translational modification sites have been identified on YBX1, while few were confirmed in vivo, an obvious and immediate task that scientists are facing is to confirm most if not all of the identified sites in vivo. If confirmed, the important biological role of each modified site can be further examined in cancer or other YBX1 related diseases. Another daunting task once the modification site is confirmed is that efforts need to be put into the discovery of the enzymes that may catalyze these specific modifications. Often, enzymes are better targets in the development of drugs to treat cancer. Furthermore, as cutting edge technologies emerge at an amazing pace, it should not come as a major surprise that more post-translational modification sites will be discovered on YBX1 in the near future. Moreover, post-translational modification of proteins is often cellular-context dependent. It is not difficult to imagine that quite different modifications of YBX1 could be identified in different types of cancer and disease states. These unique post-translational modifications of YBX1 could represent a disease-specific signature which may help with diagnosis and treatment of that specific disease.
To conclude, understanding the fascinating state of post-translational modification of YBX1 will not only lead to a better understanding of the mechanisms underlying biological processes regulated by YBX1, but will also help to develop effective pathway-specific therapeutic strategies against YBX1 in different types of cancer and YBX1-related diseases.