p73

p73 is a protein related to the p53 tumor protein. Because of its structural resemblance to p53, it has also been considered a tumor suppressor. It is involved in cell cycle regulation, and induction of apoptosis. Like p53, p73 is characterized by the presence of different isoforms of the protein. This is explained by splice variants, and an alternative promoter in the DNA sequence.

TP73
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 4GUQ, 1COK, 1DXS, 2KBY, 2MPS, 2WQI, 2WQJ, 2WTT, 2XWC, 3VD0, 3VD1, 3VD2, 4A63, 4G82, 4G83, 4GUO
Identifiers
Aliases	TP73, P73, tumor protein p73, CILD47
External IDs	OMIM: 601990 MGI: 1336991 HomoloGene: 3960 GeneCards: TP73
Gene location (Human) Chr. Chromosome 1 (human)[1] Band 1p36.32 Start 3,652,516 bp[1] End 3,736,201 bp[1]
Gene location (Mouse) Chr. Chromosome 4 (mouse)[2] Band 4 E2|4 83.79 cM Start 154,140,706 bp[2] End 154,224,665 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in right uterine tube bronchial epithelial cell cerebellar hemisphere skin of abdomen minor salivary gland bone marrow cells vagina prostate right lung thymus Top expressed in lip secondary oocyte Jacobson's organ neuron esophagus hair follicle skin of back right lung lobe skin of abdomen cerebellar cortex More reference expression data BioGPS More reference expression data
Gene ontology Molecular function DNA binding sequence-specific DNA binding DNA-binding transcription activator activity, RNA polymerase II-specific transcription factor binding chromatin binding metal ion binding RNA polymerase II cis-regulatory region sequence-specific DNA binding damaged DNA binding protein binding identical protein binding protein kinase binding p53 binding DNA-binding transcription factor activity MDM2/MDM4 family protein binding DNA-binding transcription factor activity, RNA polymerase II-specific Cellular component cytoplasm Golgi apparatus intracellular membrane-bounded organelle transcription regulator complex cell junction chromatin nucleus mitochondrion nucleoplasm cytosol Biological process negative regulation of neuron apoptotic process positive regulation of oligodendrocyte differentiation intrinsic apoptotic signaling pathway in response to DNA damage by p53 class mediator regulation of transcription, DNA-templated negative regulation of neuron differentiation kidney development cellular response to UV negative regulation of transcription by RNA polymerase II protein tetramerization transcription, DNA-templated cellular response to DNA damage stimulus mitotic G1 DNA damage checkpoint signaling response to organonitrogen compound intrinsic apoptotic signaling pathway in response to DNA damage regulation of mitotic cell cycle positive regulation of apoptotic process regulation of gene expression DNA mismatch repair cell cycle negative regulation of cardiac muscle cell proliferation viral process negative regulation of JUN kinase activity response to gamma radiation response to X-ray positive regulation of transcription by RNA polymerase II DNA damage response, signal transduction by p53 class mediator resulting in transcription of p21 class mediator negative regulation of cell population proliferation apoptotic process regulation of signal transduction by p53 class mediator transcription by RNA polymerase II regulation of apoptotic process positive regulation of protein insertion into mitochondrial membrane involved in apoptotic signaling pathway positive regulation of transcription, DNA-templated regulation of hematopoietic stem cell differentiation Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 7161 22062 Ensembl ENSG00000078900 ENSMUSG00000029026 UniProt O15350 Q9JJP2 RefSeq (mRNA) NM_001126240 NM_001126241 NM_001126242 NM_001204184 NM_001204185 NM_001204186 NM_001204187 NM_001204188 NM_001204189 NM_001204190 NM_001204191 NM_001204192 NM_005427 NM_001126330 NM_001126331 NM_011642 RefSeq (protein) NP_001119712 NP_001119713 NP_001119714 NP_001191113 NP_001191114 NP_001191115 NP_001191116 NP_001191117 NP_001191118 NP_001191119 NP_001191120 NP_001191121 NP_005418 NP_001119802 NP_001119803 NP_035772 Location (UCSC) Chr 1: 3.65 – 3.74 Mb Chr 4: 154.14 – 154.22 Mb PubMed search [3] [4]
Wikidata
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p73, also known as tumor protein 73 (TP73), protein was the first identified homologue of the tumor suppressor gene, p53. Like p53, p73 has several variants. It is expressed as distinct forms differing at either at the C- or the N-terminus. Currently, six different C-terminus splicing variants have been found in normal cells. The p73 gene encodes a protein with a significant sequence homology and a functional similarity with the tumor suppressor p53. The over-expression of p73 in cultured cells promotes a growth arrest and/or apoptosis similarly to p53.

The p73 gene has been mapped to a chromosome region (1p36. 2-3) a locus commonly deleted in various tumor entities and human cancers. Similar to p53 the protein product of p73 induces cell cycle arrest or apoptosis, hence its classification as a tumor suppressor. However unlike its counterpart, p73 is infrequently mutated in cancers. Perhaps, even more shocking is the fact that p73 – deficient mice do not show a tumorigenic phenotype. A deficiency of p53 almost certainly leads to unchecked cell proliferation and is noted in 60% of cancers.

Analyses of many tumors typically found in humans including breast and ovarian cancer show a high expression of p73 when compared to normal tissues in corresponding areas. Adenoviruses that cause cellular transformations have also been found to result in increased p73 expression. Furthermore, recent finding are suggesting that over-expression of transcription factors involved in cell cycle regulation and synthesis of DNA in mammalian cells (e.g.: E2F-1) induces the expression of p73. Many researchers believe that these results imply that p73 may not be a tumor suppressor but rather an oncoprotein. Some suggest that the TP73 locus encodes both a tumor suppressor (TAp73) and a putative oncogene (ΔNp73). This is a strong theory and causes much confusion, as it is unknown which of the two p73 variants is over-expressed and ultimately plays a role in tumorigenesis.

Genes of the p53 family are known to be complex. The viral oncoproteins (e.g. Adenovirus E1B) that efficiently inhibit p53 function are unable to inactivate p73, and those that seem to inhibit p73 have no effect on p53.

Debate persists about the exact function of p73. Recently it has been reported that p73 is enriched in the nervous system and that the p73-deficient mice, which do not exhibit an increased susceptibility to spontaneous tumorigenesis, have neurological and immunological defects. These results have been expanded and it has also been shown that p73 is present in early stages of neurological development and neuronal apoptosis by blocking the proapoptotic function of p53. This strongly implicates p73 as playing a large role in cellular differentiation.