CD120b TNFRII ( TNF Receptor Type 2), TNFR p75, TNFRSF1B
Molecule TypeAntigen ExpressionMolecular Weight
Min / Max
Non-lineage Restricted Molecule
Type 1 glycoprotein
Hematopoietic Cell
Nonhematopoietic Cell
Myeloid Cell
75 / 75
85 / 85

Expression
Most cell types (hematopoietic and nonhematopoietic cells) express the receptor CD120β for TNF.  CD120β expression is highest on myeloid cells.

Structure
MOLECULAR FAMILY NAME: Belongs to the tumor necrosis factor family.

CD120β is a single-pass type-1 a 415 aa glycoprotein.  It contains a 235 aa extracellular domain which contains 4 tandemly repeated cysteine-rich motifs and  3 potential N-linked glycosylation sites, a 30 aa transmembrane and an 174 aa intracellular cytoplasmic domain.  The extracellular domain also has a pre-ligand-binding assembly domain that promotes the formation of receptor complexes and trimerization of CD120β molecules particularly after activation by ligand binding.  Unlike CD120α, CD120β does not have a death domain. 

MOLECULAR MASS
Cell Type Unreduced Reduced
75 - 85 kDa

POST-TRANSCRIPTIONAL MODIFICATION

Alternative splicing yields 2 different isoforms.

POST-TRANSLATIONAL MODIFICATION

CD120β is cleaved by the metalloprotease TACE into a soluble form that retains the ability to bind TNF.

Ligands
LIGANDS AND MOLECULES ASSOCIATED WITH CD120β

Both receptors bind TNFa and LTa with a relatively high affinity of kDa < 10-9 M-1.  Membrane bound and soluble TNF and LTa bind to CD120β.  A 3rd TNF-like protein, LTb forms heterocomplexes with LTa at the cell surface but these do not bind CD120β but to a separate LTb receptor.  Several different proteins can associate directly or indirectly with the cytoplasmic parts of CD120β, including TNF receptor-associated factors (TRAF), TNF receptor-associated proteins (TRAP), TNF receptor-associated kinase (TRAK) and TNFR1-associated death domain protein (TRADD).

Function
CD120β is a receptor for both TNFa and TNFb (LTa ) which is cytokines produced primarily by macrophages/monocytes, activated T and NK cells in response to bacterial, viral and parasitic infections.  CD120β mediates pro-inflammatory cellular responses, programmed cell death and anti-viral activity.  TNF mediates a wide variety of effects including tumor necrosis, anorexia, fever, induction of other cytokines, cell differentiation and apoptosis.  Crosslinking of the TNF receptors by soluble or membrane bound TNF leads to signaling which is mediated by a variety of associated molecules leading to different pathways.  Unlike CD120α, whose expression is largely unmodulated, the number of CD120β molecules on the cell surface will be determined by the level of expression induced and shedding of the receptor as a result of proteolytic cleavage.  This has led to the proposal that a cell's response to TNF is determined by the ratio of CD120α to CD120β. 

BIOCHEMICAL ACTIVITY: No information.

DISEASE RELEVANCE AND FUNCTION OF CD120β IN INTACT ANIMAL

CD120β deficient mice have shown that the receptor is important in low doses TNF-induced lethality, thymocyte proliferation and depressed Langerhans cell migration.  It also appears to play an important role in models of malaria and microvascular endothelial cell damage and multi-organ inflammation.  Studies in mice suggest a role of CD120β in protecting neurons from apoptosis by stimulating antioxidative pathways.  A common polymorphic variant substituting Met for Arg at position 196 is associated with hyperandrogenism, polycystic ovary syndrome and systemic lupus erythematosus.

Comments
MOLECULAR INTERACTIONS-
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD120β: No information.

SUBSTRATES: No information.

ENZYMES WHICH MODIFY CD120β: No information.


Database accession numbers
AnimalPIRSWISSPROTEMGBL/GENBANK
 
HumanEntrezgene 7133P20333
MouseM60469
Antibodies
MR2-1   View Reactivity

Revised June 25, 2008


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