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3kho

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Crystal structure of murine Ig-beta (CD79b) homodimer

Structural highlights

3kho is a 2 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3.11Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CD79B_MOUSE Required in cooperation with CD79A for initiation of the signal transduction cascade activated by the B-cell antigen receptor complex (BCR) which leads to internalization of the complex, trafficking to late endosomes and antigen presentation. Enhances phosphorylation of CD79A, possibly by recruiting kinases which phosphorylate CD79A or by recruiting proteins which bind to CD79A and protect it from dephosphorylation.^[1] ^[2] ^[3] ^[4]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

The B cell antigen receptor (BCR) plays an essential role in all phases of B cell development. Here we show that the extracellular domains of murine and human Igbeta form an I-set immunoglobulin-like structure with an interchain disulfide between cysteines on their G strands. Structural and sequence analysis suggests that Igalpha displays a similar fold as Igbeta. An Igalphabeta heterodimer model was generated based on the unique disulfide-bonded Igbeta dimer. Solution binding studies showed that the extracellular domains of Igalphabeta preferentially recognize the constant region of BCR with mu chain specificity, suggesting a role for Igalphabeta to enhance BCRmu chain signaling. Cluster mutations on Igalpha, Igbeta, and a membrane-bound form of immunoglobulin (mIgM) based on the structural model identified distinct areas of potential contacts involving charged residues on both subunits of the coreceptor and the Cmu4 domain of mIgM. These studies provide the first structural model for understanding BCR function.

Structural and functional studies of Igalphabeta and its assembly with the B cell antigen receptor.,Radaev S, Zou Z, Tolar P, Nguyen K, Nguyen A, Krueger PD, Stutzman N, Pierce S, Sun PD Structure. 2010 Aug 11;18(8):934-43. PMID:20696394^[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Taddie JA, Hurley TR, Hardwick BS, Sefton BM. Activation of B- and T-cells by the cytoplasmic domains of the B-cell antigen receptor proteins Ig-alpha and Ig-beta. J Biol Chem. 1994 May 6;269(18):13529-35. PMID:8175787
↑ Siemasko K, Eisfelder BJ, Stebbins C, Kabak S, Sant AJ, Song W, Clark MR. Ig alpha and Ig beta are required for efficient trafficking to late endosomes and to enhance antigen presentation. J Immunol. 1999 Jun 1;162(11):6518-25. PMID:10352267
↑ Li C, Siemasko K, Clark MR, Song W. Cooperative interaction of Ig(alpha) and Ig(beta) of the BCR regulates the kinetics and specificity of antigen targeting. Int Immunol. 2002 Oct;14(10):1179-91. PMID:12356683
↑ Fuentes-Panana EM, Bannish G, van der Voort D, King LB, Monroe JG. Ig alpha/Ig beta complexes generate signals for B cell development independent of selective plasma membrane compartmentalization. J Immunol. 2005 Feb 1;174(3):1245-52. PMID:15661879
↑ Radaev S, Zou Z, Tolar P, Nguyen K, Nguyen A, Krueger PD, Stutzman N, Pierce S, Sun PD. Structural and functional studies of Igalphabeta and its assembly with the B cell antigen receptor. Structure. 2010 Aug 11;18(8):934-43. PMID:20696394 doi:10.1016/j.str.2010.04.019