Why are we an umbrella organization?
The hnRNPs are as much of a community in the cell as we are at the HNRNP Family Foundation.
The HNRNPs are genes encoding for the heterogenous nuclear ribonucleoproteins (also called hnRNPs when referring to the proteins). The hnRNPs are a large family of ~30 RNA binding proteins. These proteins are incredibly important in the cell and contribute to many aspects of RNA processing of many genes.
alternative splicing (deciding which version of a gene is expressed)
mRNA stabilization (making sure the expressed genes don’t get degraded)
regulation of transcription (deciding which genes get expressed where)
and regulation of transcription (helping decide which mRNAs are made into proteins)
We also know that the hnRNPs look similar on a molecular level. Additionally, the hnRNPs can work together and compensate for each other.
The importance of the HNRNP genes
hnRNPs have been of great interest in the medical world for a long time due to their involvement in cancers and neurodegenerative disorders, which is often through changes in expression of the hnRNPs themselves. In contrast, the HNRNP-RNDDs are caused by variants within the genes.
RNA binding proteins in general have a significant role in neurodevelopment.
Each hnRNP has a unique role, although they often overlap. From the time a gene is made into RNA to the point its made into protein, an hnRNP is involved.
To describe the HNRNPs, we use italics for the gene. For the protein, we use hnRNP. Some of the important functions of the hnRNPs are listed below. You can see that we know a lot more about some compared to others. Those with similar colors below are more related to each other.
hnRNPC was one of the first ones discovered! It is known to be involved in RNA splicing and sorts mRNA transcripts by size, ultimately packaging them to be translated.
hnRNPH1 is involved in alternative splicing.
hnRNPR is known to regulate both translation and post-transcriptional activity.
hnRNPD, also called AUF1, is primarily involved in rapid mRNA decay. It can also stimulate transcription. hnRNP also binds to the end of chromosomes (the telomeres).
hnRNPH2 is involved in alternative splicing and shuttling mRNAs to and from the nucleus.
hnRNPQ, also known as SYNCRIP, has two names since it was identified by multiple researchers around the same time. hnRNPQ is involved in dendritic development in the brain, as well as maturation of mRNA.
hnRNPG (more well known as RBMX because it is on the X chromosome) is involved in modulating RNA splicing.
hnRNPK regulates transcription, translation, and post-translational modifications. Additionally, hnRNPK is involved in cellular stress and is known to regulate genes implicated in osteoclast (early bone cells) differentiation, among other genes.
hnRNPU is the largest hnRNP. It is primarily involved in transcription and alternative splicing, but also in X inactivation in females.
hnRNPUL2 is hnRNPU-like 2. It is a minor hnRNP that is involved in regulation of other hnRNPs.