Cytoplasmic FMR1-interacting protein 2 is a protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the CYFIP2 gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

. Cytoplasmic FMR1 interacting protein is a 1253 amino acid long protein and is highly conserved having a 99% homology to the mouse protein. It is expressed mainly in brain tissues, white blood cells and the kidney.

Interactions

CYFIP2 has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with FMR1

FMR1

FMR1 is a human gene that codes for a protein called fragile X mental retardation protein, or FMRP. This protein, most commonly found in the brain, is essential for normal cognitive development and female reproductive function...

. CYFIP2 is a p-53 inducible protein and also interacts with the Fragile=X mental retardation protein.

RNA editing

The pre-mRNA

Messenger RNA

Messenger RNA is a molecule of RNA encoding a chemical "blueprint" for a protein product. mRNA is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. Here, the nucleic acid polymer is translated into a polymer of amino acids: a protein...

 of this protein is subject to RNA editing

RNA editing

The term RNA editing describes those molecular processes in which the information content in an RNA molecule is altered through a chemical change in the base makeup. To date, such changes have been observed in tRNA, rRNA, mRNA and microRNA molecules of eukaryotes but not prokaryotes...

. The editing site was previously recorded as a single nucleotide polymorphism (rs3207362) in the dbSNP.

Type

A to I RNA editing is catalyzed by a family of adenosine deaminase

Adenosine deaminase

Adenosine deaminase is an enzyme involved in purine metabolism. It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues.-Reactions:...

s acting on RNA (ADARs) that specifically recognize adenosines within double-stranded regions of pre-mRNAs and deaminate them to inosine

Inosine

Inosine is a nucleoside that is formed when hypoxanthine is attached to a ribose ring via a β-N9-glycosidic bond....

. Inosines are recognised as guanosine by the cells translational machinery. There are three members of the ADAR family ADARs 1-3 with ADAR1

ADAR

Double-stranded RNA-specific adenosine deaminase is an enzyme that in humans is encoded by the ADAR gene.-Further reading:...

  and ADAR2

ADARB1

Double-stranded RNA-specific editase 1 is an enzyme that in humans is encoded by the ADARB1 gene.ADAR2 requires the small molecule inositol hexakisphosphate for proper function.-Further reading:...

 being the only enzymatically active members. ADAR3

ADARB2

Double-stranded RNA-specific editase B2 is an enzyme that in humans is encoded by the ADARB2 gene.-Further reading:...

 is thought to have a regulatory role in the brain. ADAR1 and ADAR 2 are widely expressed in tissues while ADAR3 is restricted to the brain. The double stranded regions of RNA are formed by base-pairing between residues in the close to region of the editing site with residues usually in a neighboring intron but can be an exonic sequence. The region that base pairs with the editing region is known as an Editing Complementary Sequence (ECS).

Site

An editing site was found in the pre-mRNA of this protein. The substitution occurs within amino acid position 320 in humans and also in mice.A possible double stranded RNA region has not been detected for this pre-mRNA. No double stranded region required by ADARs has predicted.Immunoprecipitation experiments and RNA interference have shown that ADAR 2 is likely to be the main editing enzyme for this site with ADAR 1 having a minor role.

Regulation

Editing seems to be differentially regulated in different tissues .The highest level of editing occurring in the cerebellum with lower frewquency of editing detected in human lung, prostrate and uterus tissues.Editing frequency varies from 30-85% depending on tissue. There is some evidence for a decrease in CYFIP2 editing with increased age.

Structural

Editing results in a codon change resulting in a glycine

Glycine

Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

 being translated instead of a lysine

Lysine

Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....

.

Functional

Currently unknown but editing may have role in regulation of apoptotic functions of this protein.It is thought that since the protein is p53 inducible that the protein maybe pro-apopototic. Also ADAR1 knock out mice show increase in apoptosis which indicates editing may be involved in regulation of the cellular process.