Tumor necrosis factor receptor 2 (TNFR2), also known as tumor necrosis factor receptor superfamily member 1B (TNFRSF1B) and CD120b, is one of two membrane receptors that binds

tumor necrosis factor-alpha Tumor necrosis factor (TNF, cachexin, or cachectin; formerly known as tumor necrosis factor alpha or TNF-α) is an adipokine and a cytokine. TNF is a member of the TNF superfamily, which consists of various transmembrane proteins with a homologo ...

(TNFα). Like its counterpart, tumor necrosis factor receptor 1 (TNFR1), the extracellular region of TNFR2 consists of four cysteine-rich domains which allow for binding to TNFα. TNFR1 and TNFR2 possess different functions when bound to TNFα due to differences in their intracellular structures, such as TNFR2 lacking a death domain ( DD).

Function

The protein encoded by this gene is a member of the

tumor necrosis factor receptor The tumor necrosis factor receptor superfamily (TNFRSF) is a protein superfamily of cytokine receptors characterized by the ability to bind tumor necrosis factors (TNFs) via an extracellular cysteine-rich domain. With the exception of nerve growt ...

superfamily, which also contains TNFRSF1A. This protein and TNF-receptor 1 form a heterocomplex that mediates the recruitment of two anti-apoptotic proteins,

c-IAP1 Inhibitors of apoptosis are a group of proteins that mainly act on the intrinsic pathway that block programmed cell death, which can frequently lead to cancer or other effects for the cell if mutated or improperly regulated. Many of these inhibito ...

and c-IAP2, which possess

E3 ubiquitin ligase A ubiquitin ligase (also called an E3 ubiquitin ligase) is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquitin ...

activity. The function of IAPs in TNF-receptor signalling is unknown, however, c-IAP1 is thought to potentiate TNF-induced apoptosis by the

ubiquitination Ubiquitin is a small (8.6 kDa) regulatory protein found in most tissues of eukaryotic organisms, i.e., it is found ''ubiquitously''. It was discovered in 1975 by Gideon Goldstein and further characterized throughout the late 1970s and 1980s. F ...

and degradation of TNF-receptor-associated factor 2 ( TRAF2), which mediates anti-apoptotic signals. Knockout studies in mice also suggest a role of this protein in protecting neurons from apoptosis by stimulating antioxidative pathways.

Clinical significance

CNS

At least partly because TNRF2 has no intracellular death domain, TNFR2 is neuroprotective. Patients with schizophrenia have increased levels of soluble tumor necrosis factor receptor 2 ( sTNFR2).

Cancer

Targeting of TNRF2 in tumor cells is associated with increased tumor cell death and decreased progression of tumor cell growth. Increased expression of TNFR2 is found in

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or ...

cervical cancer Cervical cancer is a cancer arising from the cervix. It is due to the abnormal growth of cells that have the ability to invade or spread to other parts of the body. Early on, typically no symptoms are seen. Later symptoms may include abnormal ...

colon cancer Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum (parts of the large intestine). Signs and symptoms may include blood in the stool, a change in bowel ...

, and

renal cancer Kidney cancer, also known as renal cancer, is a group of cancers that starts in the kidney. Symptoms may include blood in the urine, lump in the abdomen, or back pain. Fever, weight loss, and tiredness may also occur. Complications can include ...

. A link between the expression of TNRF2 in tumor cells and late-stage cancer has been discovered. TNFR2 plays a significant role in tumor cell growth as it has been found that the loss of TNFR2 expression is linked with increased death of associated tumor cells and a significant standstill of further growth. There is therapeutic potential in the targeting of TNFR2 for cancer treatments through TNFR2 inhibition.

Systemic Lupus Erythematous (SLE)

A small scale study of 289 Japanese patients suggested a minor increased predisposition from an amino acid substitution of the 196 allele at exon 6. Genomic testing of 81 SLE patients and 207 healthy patients in a Japanese study showed 37% of SLE patients had a polymorphism on position 196 of

exon An exon is any part of a gene that will form a part of the final mature RNA produced by that gene after introns have been removed by RNA splicing. The term ''exon'' refers to both the DNA sequence within a gene and to the corresponding sequenc ...

6 compared to 18.8% of healthy patients. The TNFR2 196R allele polymorphism suggests that even one 196R

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...

results in increased risk for SLE.

Interactions

TNFRSF1B has been shown to interact with: * TRAF2, and * TTRAP.

References

External links

* TNF receptor family {{biochem-stub