Heterogeneous Ribonucleoprotein Particle
Heterogeneous nuclear ribonucleoproteins (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.
Read more about Heterogeneous Ribonucleoprotein Particle: Functions, Examples
Famous quotes containing the word particle:
“Love is life. All, everything that I understand, I understand only because I love. Everything is, everything exists, only because I love. Everything is united by it alone. Love is God, and to die means that I, a particle of love, shall return to the general and eternal source.”
—Leo Tolstoy (18281910)