RTP3 (receptor transporter protein 3) is a gene located on

chromosome 3 Chromosome 3 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 3 spans almost 200 million base pairs (the building material of DNA) and represents about 6.5 percent of the total DNA in ...

in humans that encodes the RTP3 protein.omo sapiens (human)- Gene - NCBI"> Its expression is liver-restricted.

Gene

Aliases for RTP3 in ''Homo sapiens'' include LTM1, TMEM7, and Z3CXXC3.omo sapiens (human)- Gene - NCBI"> It is located at locus 3p21.31 and contains two exons. It spans a total of 2,974 base pairs, between bases 46497976 and 46500950 on chromosome 3.

Protein

There is only one known protein isoform in humans, which is 232 amino acids long and has a predicted molecular weight of 26.9 kDa.omo sapiens (human)- Protein - NCBI"> It has a predicted isoelectric point of 9. The protein contains a transmembrane domain near the

C-terminus The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When the protein is ...

. The protein is rich in cysteine and tryptophan and is poor in aspartic acid.

Gene regulation

Regulation of the RTP3 gene appears to be tissue-specific, as it is expressed almost exclusively in the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

, with low levels of expression in the testes, thyroid, kidney, and adrenal gland.omo sapiens (human)- Gene - NCBI"> There are some poorly-conserved binding sites for

miRNA MicroRNA (miRNA) are small, single-stranded, non-coding RNA molecules containing 21 to 23 nucleotides. Found in plants, animals and some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRN ...

molecules in the 3' untranslated region of the gene. One of these is miRNA-29, which has been found to affect progression of liver tumors in mouse models.

Homologs

Orthologs

Many animal species contain orthologs of the RTP3 gene, including various species of

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are nat ...

, and

birds Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

Paralogs

RTP3 has several paralogs in humans, including other members of the RTP family.

Interacting proteins

While there is experimental evidence RTP3 may potentially be able to interact with proteins involved in olfactory signaling, as it contains shared homology with other members of the RTP family that do so, it is unlikely that it contributes greatly to olfactory signaling pathways due to its expression being almost exclusive to the liver.

Clinical significance

The RTP3 gene has been found to be downregulated in liver carcinomas. In cell lines that do not contain

p53 p53, also known as Tumor protein P53, cellular tumor antigen p53 (UniProt name), or transformation-related protein 53 (TRP53) is a regulatory protein that is often mutated in human cancers. The p53 proteins (originally thought to be, and often s ...

, a tumor suppressor protein, RTP3 has found to be more highly expressed than in cell lines that do contain the protein.

Single-nucleotide polymorphisms In genetics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently larg ...

in the promoter and intron of the RTP3 gene have been associated with increased risk of hip fracture, suggesting possible involvement of the gene in the

TGF-β Transforming growth factor beta (TGF-β) is a multifunctional cytokine belonging to the transforming growth factor superfamily that includes three different mammalian isoforms (TGF-β 1 to 3, HGNC symbols TGFB1, TGFB2, TGFB3) and many other sign ...

signaling pathway.

References

{{reflist Genes on human chromosome 3