Heterogeneous ribonucleoprotein particle


Heterogeneous ribonucleoprotein particle

Heterogeneous ribonucleoprotein particles (hnRNPs) are complexes of RNA and protein present in the cell nucleus during gene transcription and subsequent post-transcriptional modification of the newly synthesized RNA (pre-mRNA). The presence of the proteins bound to a pre-mRNA molecule serves as a signal that the pre-mRNA is not yet fully processed and ready for export to the cytoplasm. After splicing has occurred, the proteins remain bound to spliced introns and target them for degradation.

The proteins involved in the hnRNP complexes are collectively known as heterogeneous ribonucleoproteins. They include protein K and polypyrimidine-tract binding protein (PTB), which is regulated by phosphorylation catalyzed by protein kinase A and is responsible for suppressing RNA splicing at a particular exon by blocking access of the spliceosome to the polypyrimidine tract.

FUNCTION:1. Prevent folding of pre-mRNA into secondary structures that may inhibit its interactions with other proteins.2. May associate with the splicing apparatus.3. Transport of mRNA out of the nucleus.

References

* Xie J, Lee JA, Kress TL, Mowry KL, Black DL. (2003). Protein kinase A phosphorylation modulates transport of the polypyrimidine tract-binding protein. "Proc Natl Acad Sci USA" 100(15):8776-81.
* Takimoto M, Tomonaga T, Matunis M, Avigan M, Krutzsch H, Dreyfuss G, Levens D. (1993). Specific binding of heterogeneous ribonucleoprotein particle protein K to the human c-myc promoter, in vitro. "J Biol Chem" 268(24):18249-58.
* Watson JD, Baker TA, Bell SP, Gann A, Levine M, Losick R. (2004). Molecular Biology of the Gene, ch. 9 and 10. Peason Benjamin Cummings; CSHL Press. 5th ed.


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Protein K (gene expression) — Protein K is a human protein found in the cell nucleus that binds to pre messenger RNA (mRNA) as a component of heterogeneous ribonucleoprotein particles. The simian homolog is known as protein H16 . Both proteins bind to single stranded DNA as… …   Wikipedia

  • HNRNPC — Heterogeneous nuclear ribonucleoprotein C (C1/C2), also known as HNRPC, is a human gene.cite web | title = Entrez Gene: HNRPC heterogeneous nuclear ribonucleoprotein C (C1/C2)| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene… …   Wikipedia

  • Hepatitis B — Classification and external resources Electron micrograph of hepatitis B virus ICD 10 B …   Wikipedia

  • DEK (gene) — DEK oncogene PDB rendering based on 1q1v …   Wikipedia

  • cell — cell1 cell like, adj. /sel/, n. 1. a small room, as in a convent or prison. 2. any of various small compartments or bounded areas forming part of a whole. 3. a small group acting as a unit within a larger organization: a local cell of the… …   Universalium

  • Immunoprecipitation — (IP) is the technique of precipitating a protein antigen out of solution using an antibody that specifically binds to that particular protein. This process can be used to isolate and concentrate a particular protein from a sample containing many… …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.