Mapping the Functional Regions of heteroribonucleoparticle K protein
The heterogenous nuclear ribonucleoprotein (hnRNP) K protein is a multifunctional protein that plays a key role in many insulin-responsive pathways. It has gained considerable recognition for its ability to engage a host of molecular partners that are involved in signal transduction, transcription, translation, and RNA processing. As a result, it has been hypothesized that the hnRNP K protein serves as a docking molecule that links signal transduction pathways to nucleic acid-dependent processes.
Recent studies on the primary structure of K protein have provided evidence for this hypothesis. For example, studies reveal that both a nuclear localization signal and a nuclear shuttling domain exist on the K protein. These findings suggest that the K protein may play a key role in transcription and the export of mRNA.
In addition to its ability to shuttle between the nucleus and the cytoplasm, evidence suggests that the K protein also serves as a scaffolding molecule in signal transduction pathways. This theory is supported in part by the discovery of the highly interactive K protein region, or KI region.
The KI region is a proline-rich 97 amino acid site containing SH3-binding domains, which enable it to bind with a variety of kinases including PKCd and Src family kinases.
Despite the recent discovery of this highly interactive domain, little is known about the secondary and tertiary structure of the KI region. In fact, it is not known whether the KI region is a true and autonomous domain or if it is simply a region. Therefore the aim of this project is to utilize proteolysis and mass spectroscopy techniques to map the KI region of hnRNP K protein in order to gain a better understanding of the mechanisms by which this region interacts with key signal transduction molecules.
