Allregulin

Allregulin (ARLN) is a protein which in humans is encoded by the C4orf3 gene.^[5] ARLN is a small ER transmembrane protein that regulates calcium homeostasis through SERCA (sarco-endoplasmic reticulum calcium ATPase). It is also known as C4orf3 and HCVFTP1 (hepatitis C virus F protein-transactivated protein 1).^[6]

C4orf3
Identifiers
Aliases	C4orf3, chromosome 4 open reading frame 3, HCVFTP1, ALN
External IDs	MGI: 1914954; HomoloGene: 88390; GeneCards: C4orf3; OMA:C4orf3 - orthologs
Gene location (Human) Chr. Chromosome 4 (human)[1] Band 4q26 Start 119,296,419 bp[1] End 119,304,445 bp[1]
Gene location (Mouse) Chr. Chromosome 3 (mouse)[2] Band 3|3 G1 Start 122,717,852 bp[2] End 122,719,833 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in endothelial cell skin of arm inferior ganglion of vagus nerve medulla oblongata superior vestibular nucleus subthalamic nucleus pons saphenous vein human penis urethra Top expressed in esophagus stomach lung urinary bladder ileum duodenum yolk sac bone marrow proximal tubule pancreas More reference expression data BioGPS n/a
Orthologs Species Human Mouse Entrez 401152 67704 Ensembl ENSG00000164096 ENSMUSG00000054091 UniProt Q8WVX3 Q99M08 RefSeq (mRNA) NM_001170330 NM_001001701 NM_024461 RefSeq (protein) NP_001001701 NP_001163801 NP_077781 Location (UCSC) Chr 4: 119.3 – 119.3 Mb Chr 3: 122.72 – 122.72 Mb PubMed search [3] [4]
Wikidata
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Gene

Chromosome 4 open reading frame 3 is a protein encoding gene that is located on chromosome 4 with specific location 4q26. It has a total of 3 exons.^[6] The gene acts upstream or within negative regulation of ATPase-coupled calcium transmembrane transporter activity. The protein encoded by this gene is located in the endoplasmic reticulum membrane as an integral component. It is ubiquitously expressed in the esophagus, fat, and kidney.^[6] It is a newly discovered tissue specific regulator of SERCA (sarco-endoplasmic reticulum calcium ATPase), its function to interact with the inhibitory groove of SERCA.^[7]

mRNA

C4orf3 transcript variant 1 encodes for a mRNA sequence that is 2975 nucleotides in length. It is composed of three exons, two of which are embedded in the coding sequence and one that spans the rest of the sequence.^[8] There is no 5' UTR because the coding sequence begins at the beginning of the sequence and the 3' UTR is 209 nucleotides long.^[8]

Protein

ARLN is a small ER transmembrane protein that regulates calcium homeostasis through SERCA.^[9] The molecular weight is 7.6 kDa. Isoform 1 is 199 amino acids long, however there is also a smaller isoform, that is 66 amino acids long.^[8] The second isoform is the latter part of the first isoform. The protein and its orthologs are rich in arginine.^[10] There is a transmembrane domain present near the C-terminus (amino acids 177-199).^[11] This transmembrane domain is well conserved in orthologs.

Homology

Graph illustrating the relationship between the estimated date of divergence and the m value for all 20 orthologs of C4orf3 and a few species from each group for cytochrome c and fibrinogen alpha.

C4orf3 orthologs are found in most mammals, mainly in primates, but also in whales, dolphins, foxes and other mammals. There is one bird (Phalacrocorax carbo) where a C4orf3 ortholog is found. The C-terminus of the protein is highly conserved in these orthologs.

There are no human paralogs present for the gene.^[12]