A ribonucleoprotein particle or RNP is vessicle

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

formed between RNA and

RNA-binding protein RNA-binding proteins (often abbreviated as RBPs) are proteins that bind to the double or single stranded RNA in cells and participate in forming ribonucleoprotein complexes. RBPs contain various structural motifs, such as RNA recognition motif ...

s (RBPs). The term RNP foci can also be used to denote intracellular compartments involved in processing of RNA transcripts.

RNA/RBP complexes

RBPs interact with RNA through various structural motifs.

Aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

residues in RNA-binding proteins result in stacking interactions with RNA. Lysine residues in the

helical Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A t ...

portion of RNA binding proteins help to stabilize interactions with other

nucleic acids Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ...

as a result of the force of attraction between the positively-charged lysine

side chain In organic chemistry and biochemistry, a side chain is a chemical group that is attached to a core part of the molecule called the "main chain" or backbone. The side chain is a hydrocarbon branching element of a molecule that is attached to a ...

s and the negatively-charged

phosphate In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

"backbone" of RNA. It is hypothesized that RNA sequences in the

3'-untranslated region In molecular genetics, the three prime untranslated region (3′-UTR) is the section of messenger RNA (mRNA) that immediately follows the translation termination codon. The 3′-UTR often contains regulatory regions that post-transcriptionally ...

determine the binding of RBPs, and that these RBPs determine the post-transcriptional fate of mRNAs.

RNP granules

RNP granules are a highly diverse group of compartments. These include stress granules, processing bodies, and exosomes in somatic cells. Many RNP granules are cell type and/or species specific. For example, chromatoid bodies are found only in male germ cells, whereas transport granules have so far been found only in neurons and

oocytes An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female g ...

. RNP granules function mainly by physically separating or associating transcripts with proteins. They function in the storage, processing, degradation and transportation of their associated transcripts. RNP granules have been shown to have particular importance in cells where

post-transcriptional regulation Post-transcriptional regulation is the control of gene expression at the RNA level. It occurs once the RNA polymerase has been attached to the gene's promoter and is synthesizing the nucleotide sequence. Therefore, as the name indicates, it occ ...

is of vital importance. For example, in neurons where transcripts must be transported and stored in dendrites for the formation and strengthening of connections, in oocytes/embryos where mRNAs are stored for years before being translated, and in developing sperm cells where transcription is halted before development is complete.

References

Cell biology {{Cell-biology-stub

RNA/RBP complexes

RNP granules

See also

References