|CD213a2||IL13Rα 2 (interleukin 13 receptor, α2)|
|Molecule Type||Antigen Expression||Molecular Weight|
Min / Max
|Non-lineage Restricted Molecule|
Type 1 glycoprotein
Blood Cell, Peripheral
|60 / 60|
70 / 70
|CD213a2 is expressed on B cells, monocytes, fibroblasts and endothelial cells. CD213a2 is also expressed on cord blood, a subset peripheral blood lymphocytes, subpopulations of peripheral blood lymphocytes, immature dendritic cells and subsets of B lymphocytes from tonsil, blood and colon. |
|MOLECULAR FAMILY NAME: Belongs to the type-1 cytokine receptor family.|
CD213a2 is a single-pass type-1 354 aa glycoprotein. It contains a putative 26 aa signal peptide, a 317 aa extracellular domain with a fibronectin-like type-3 domain and typical cytokine receptor motifs, a 20 aa transmembrane region and a short 17 aa intracellular cytoplasmic domain. The extracellular domain is closely related to that of CD213a1 but the residue cytoplasmic domain is much shorter suggesting that the 2 receptors are functional distinct. It is structurally similar to the CD125 (IL-5a) chain with a 51% aa sequence similarity and a 27% identity. Similar to CD125, the extracellular region of the CD213α2 chain consists of a N-terminal region of about 100 aa with a sequence similarity to the equivalent portion of the CD123 (IL-3Ra) chain and the CD116 (GM-CSFRa) chain, followed by a cytokine receptor domain and a fibronectin type 3 domain that includes the WSXWS motif. The WSXWS motif appears to be necessary for protein protein folding and thereby efficient intracellular transport and cell-surface receptor binding.
Human CD213a2 contains a putative consensus phosphorylation site that may interact with SH2 containing signaling molecules.
POST-TRANSLATIONAL MODIFICATION OF CD213a2
CD213a2 has a 27 aa N-terminal residue of human and mouse which is nearly identical.
|The human IL-13Ra chain is expressed in COS-7 cells binds human IL-13 with a high affinity of kDa = 220-280 pM, whereas COS-7 cells transfected with the mouse IL-13Ra chain cDNA bind mouse IL-13 with a low affinity of kDa = 2-10 pM. In both species, the IL-13Ra chain also associates with CD124 to form a receptor capable of binding both IL-13 and IL-4 with a high affinity and mediating signal transduction events. This interaction may explain the apparent discrepancy in the ability of the human, but not mouse, IL-13Ra chain to bind IL-13 with a high affinity. Untransfected COS-7 cells express low levels of CD124 which might associate with the transfected human, but not mouse, IL-13Ra chain to form a functional high-affinity binding site for IL-13. Crosslinking experiments have identified an IL-13 binding protein of approximately 60 kDa-70 kDa, which probably corresponds to the IL-13Ra chain.|
|IL-13 binds cells through either a combination with CD213α1 and CD124 or through CD213α2. In both cases, the common γ chain appears to be necessary for signaling. IL-13 though its receptors regulates, inflammation, cell signaling and immune regulation. It inhibits the production of pro-inflammatory cytokines and chemokines from monocytes and macrophages. IL-13 upregulates several cell-surface molecules, including MHC class II and CD23 and it can act as a costimulus for B-cell proliferation and Ig synthesis and class switching. IL-13 is not restricted in function to lymphocytes and has activities on progenitor cells and endothelial. CD213a2 receptors are involved in cell signaling and immune regulation. There is a novel mechanism by which IFN-g can regulate IL-13 responses. CD213a2 inhibits binding of IL-13 to the IL-13 cell surface receptor. IL-13 and IL-4 mediate similar biological functions except that they do not regulate T cell functions. The protein encoded by CD213α2 is closely related to CD213α1, a subunit of the IL-13 receptor complex. The protein binds IL-13 with high affinity but not IL-4 and lacks the cytoplasmic domain, and does not appear to function as a signal mediator. It is reported to play a role in the internalization of IL-13.|
BIOCHEMICAL ACTIVITY: No information.
DISEASE RELEVANCE AND FUNCTION OF CD213a2 IN INTACT ANIMAL
CD213α2 can reverse IL-13 airway hyper-responsiveness, suggesting a possible use in asthma.
|The human and mouse IL-13Ra chain sequences share the same overall topology, but show only limited aa sequence identity. It remains to be determined whether additional IL-13R subunits exist and whether, in fact, these molecules are true species orthologues. The accession numbers and aa sequences are given in CD124.|
MOLECULAR INTERACTIONS -
PROTEINS AND DNA ELEMENTS WHICH REGULATE TRANSCRIPTION OF CD213a2 : No information.
SUBSTRATES: No information.
ENZYMES WHICH MODIFY CD213a2 : No information.
Database accession numbers
Revised June 25, 2008