Coilin 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 COIL 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...

.

Coilin protein is one of the main molecular components of Cajal bodies

Cajal body

Cajal bodies are spherical sub-organelles of 0.3-1.0 µm in diameter found in the nucleus of proliferative cells like embryonic cells and tumor cells, or metabolically active cells like neurons. In contrast to cytoplasmic organelles, CBs lack any phospholipid membrane which would separate their...

 (CBs). Cajal bodies are nuclear suborganelles of varying number and composition that are involved in the post-transcriptional modification

Post-transcriptional modification

Post-transcriptional modification is a process in cell biology by which, in eukaryotic cells, primary transcript RNA is converted into mature RNA. A notable example is the conversion of precursor messenger RNA into mature messenger RNA , which includes splicing and occurs prior to protein synthesis...

 of small nuclear and small nucleolar RNAs. In addition to its structural role, coilin acts as glue to connect the CB to the nucleolus

Nucleolus

The nucleolus is a non-membrane bound structure composed of proteins and nucleic acids found within the nucleus. Ribosomal RNA is transcribed and assembled within the nucleolus...

. The N-terminus of the coilin protein directs its self-oligomerization while the C-terminus influences the number of nuclear bodies assembled per cell. Differential methylation

Methylation

In the chemical sciences, methylation denotes the addition of a methyl group to a substrate or the substitution of an atom or group by a methyl group. Methylation is a form of alkylation with, to be specific, a methyl group, rather than a larger carbon chain, replacing a hydrogen atom...

 and phosphorylation

Phosphorylation

Phosphorylation is the addition of a phosphate group to a protein or other organic molecule. Phosphorylation activates or deactivates many protein enzymes....

 of coilin likely influences its localization among nuclear bodies and the composition and assembly of Cajal bodies. This gene has pseudogene

Pseudogene

Pseudogenes are dysfunctional relatives of known genes that have lost their protein-coding ability or are otherwise no longer expressed in the cell...

s on chromosome 4 and chromosome 14.

To study CBs, coilin can be combined with GFP (Green Fluorescent Protein

Green fluorescent protein

The green fluorescent protein is a protein composed of 238 amino acid residues that exhibits bright green fluorescence when exposed to blue light. Although many other marine organisms have similar green fluorescent proteins, GFP traditionally refers to the protein first isolated from the...

) to form Colin-GFP hybrid protein

Fusion protein

Fusion proteins or chimeric proteins are proteins created through the joining of two or more genes which originally coded for separate proteins. Translation of this fusion gene results in a single polypeptide with functional properties derived from each of the original proteins...

. The hybrid protein can then be used to locate CBs underneath a microscope, usually near the nucleolus of the cell. Other proteins that make up the CB include snRNP

SnRNP

snRNPs , or small nuclear ribonucleoproteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs...

s and nucleolar snoRNPs.

Coilin got its name from the coiled shaped of the CB in which it is found. It was first identified using human autoimmune serum.

Interactions

Coilin 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 SMN1

SMN1

Survival motor neuron protein is a protein that in humans is encoded by the SMN1 gene.-Interactions:SMN1 has been shown to interact with Gem-associated protein 7, GEMIN4, KPNB1, Survival of motor neuron protein-interacting protein 1, DDX20, Coilin, Small nuclear ribonucleoprotein D1, Fibrillarin,...

, SNRPB

SNRPB

Small nuclear ribonucleoprotein-associated proteins B and B is a protein that in humans is encoded by the SNRPB gene.-Interactions:SNRPB has been shown to interact with DDX20 and Coilin.-Further reading:...

, Nucleolar phosphoprotein p130

Nucleolar phosphoprotein p130

Nucleolar phosphoprotein p130 is a protein that in humans is encoded by the NOLC1 gene.-Interactions:Nucleolar phosphoprotein p130 has been shown to interact with Coilin and CEBPB.-Further reading:...

 and Ataxin 1

Ataxin 1

Ataxin-1 is a protein that in humans is encoded by the ATXN1 gene.-Interactions:Ataxin 1 has been shown to interact with Glyceraldehyde 3-phosphate dehydrogenase, Coilin, USP7 and UBE2E1.-External links:*...

.